Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Sanger”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 127 records · Page 7Linked to original sources
PubMedDate not supplied

International family-planning training for nurse practitioners.

Since the mid-1970s, the Margaret Sanger Center of Planned Parenthood of New York City has prepared nurses and nurse midwives from less developed countries to be family-planning nurse practitioners. These nurse practitioners then provide services to patients, train other staff, and manage integrated family-planning clinics. More than 120 nurses and nurse midwives have arrived in groups of 10 at the Sanger Center, with 72 attending since 1981. Each course lasts 10 weeks. The core curriculum provides trainees with skills in women's health care including contraception, in training and advocacy, and in management of clinics. Whether, in the current period of scarce resources, cross-cultural training programs of this type remain a worthwhile investment, and if so, which of their components are most important to this success, is assessed.

Africa↗
PubMed2026

A Novel Splice Variant in the COL1A1 Gene Leads to Exon 46 Skipping and Osteogenesis Imperfecta.

BACKGROUND: Osteogenesis imperfecta (OI) is a clinical and genetic disorder characterised by bone fragility, growth deficiency and skeletal deformity. Ninety per cent of OI cases are attributable to autosomal dominant variants in the COL1A1 and COL1A2 genes. METHODS: Candidate variants were identified and verified through trio whole-exome sequencing (trio-WES), copy number variation sequencing (CNV-seq) and Sanger sequencing. Minigene splicing assays were performed in HeLa and HEK293T cells with pcDNA3.1 and pcMINI-C vectors to investigate the function of the candidate variants. A systematic review of COL1A1 splicing variants and the corresponding genotype-phenotype spectrum was performed. RESULTS: Trio-WES revealed a novel heterozygous variant in the C-terminal region of the COL1A1 gene: NM_000088.4:c.3423+5G>A. Sanger sequencing confirmed the variant in both the proband (II-2) and her foetus (III-1) who were clinically suspected of having OI. The c.3423+5G>A variant causes complete skipping of Exon 46, as demonstrated by a minigene splicing assay. We retrieved 419 COL1A1 splicing variants from PubMed, excluded 15 without phenotypic data and 2 linked to Ehlers-Danlos syndrome and stratified the remaining 402 variants into three types on the basis of splice site location: (1) Variants at canonical splicing sites (77.8%, 313/402) mostly cause mild phenotypes, whereas a minority may be severe. (2) Intron variants in other locations, such as splice region variants (17.9%, 72/402), usually cause mild clinical phenotypes, and deep intronic splice variants (0.4%, 2/402) that may result in severe phenotypes. (3) Other variants (3.7%, 15/402), such as exon variants or fragment loss, are extremely rare. We also preliminarily discuss the mechanisms underlying phenotypic variability and the characteristics of C-terminal variants. CONCLUSIONS: This intron variant in COL1A1 was classified as likely pathogenic and was confirmed to disrupt COL1A1 expression. The summary analysis results also revealed a correlation among splicing variants, C-terminal region variants and disease, suggesting that variant location provides a useful framework for prognosis prediction.

Female↗
PubMed2024

Identification of four TTN variants in three families with fetal akinesia deformation sequence.

BACKGROUND: TTN is a complex gene with large genomic size and highly repetitive structure. Pathogenic variants in TTN have been reported to cause a range of skeletal muscle and cardiac disorders. Homozygous or compound heterozygous mutations tend to cause a wide spectrum of phenotypes with congenital or childhood onset. The onset and severity of the features were considered to be correlated with the types and location of the TTN variants. METHODS: Whole-exome sequencing was performed on three unrelated families presenting with fetal akinesia deformation sequence (FADS), mainly characterized by reduced fetal movements and limb contractures. Sanger sequencing was performed to confirm the variants. RT-PCR analysis was performed. RESULTS: TTN c.38,876-2 A > C, a meta transcript-only variant, with a second pathogenic or likely pathogenic variant in trans, was observed in five affected fetuses from the three families. Sanger sequencing showed that all the fetal variants were inherited from the parents. RT-PCR analysis showed two kinds of abnormal splicing, including intron 199 extension and skipping of 8 bases. CONCLUSIONS: Here we report on three unrelated families presenting with FADS caused by four TTN variants. In addition, our study demonstrates that pathogenic meta transcript-only TTN variant can lead to defects which is recognizable prenatally in a recessive manner.

Humans↗
PubMed2024

A novel start-loss mutation of the SLC29A3 gene in a consanguineous family with H syndrome: clinical characteristics, in silico analysis and literature review.

BACKGROUND: The SLC29A3 gene, which encodes a nucleoside transporter protein, is primarily located in intracellular membranes. The mutations in this gene can give rise to various clinical manifestations, including H syndrome, dysosteosclerosis, Faisalabad histiocytosis, and pigmented hypertrichosis with insulin-dependent diabetes. The aim of this study is to present two Iranian patients with H syndrome and to describe a novel start-loss mutation in SLC29A3 gene. METHODS: In this study, we employed whole-exome sequencing (WES) as a method to identify genetic variations that contribute to the development of H syndrome in a 16-year-old girl and her 8-year-old brother. These siblings were part of an Iranian family with consanguineous parents. To confirmed the pathogenicity of the identified variant, we utilized in-silico tools and cross-referenced various databases to confirm its novelty. Additionally, we conducted a co-segregation study and verified the presence of the variant in the parents of the affected patients through Sanger sequencing. RESULTS: In our study, we identified a novel start-loss mutation (c.2T > A, p.Met1Lys) in the SLC29A3 gene, which was found in both of two patients. Co-segregation analysis using Sanger sequencing confirmed that this variant was inherited from the parents. To evaluate the potential pathogenicity and novelty of this mutation, we consulted various databases. Additionally, we employed bioinformatics tools to predict the three-dimensional structure of the mutant SLC29A3 protein. These analyses were conducted with the aim of providing valuable insights into the functional implications of the identified mutation on the structure and function of the SLC29A3 protein. CONCLUSION: Our study contributes to the expanding body of evidence supporting the association between mutations in the SLC29A3 gene and H syndrome. The molecular analysis of diseases related to SLC29A3 is crucial in understanding the range of variability and raising awareness of H syndrome, with the ultimate goal of facilitating early diagnosis and appropriate treatment. The discovery of this novel biallelic variant in the probands further underscores the significance of utilizing genetic testing approaches, such as WES, as dependable diagnostic tools for individuals with this particular condition.

Humans↗
PubMed2026

[Genetic and functional characterization of a novel KIT splicing variant in a Chinese three-generation pedigree with piebaldism].

OBJECTIVES: To investigate the genetic etiology of a three-generation pedigree affected with piebaldism. METHODS: Next-generation sequencing and Sanger sequencing were employed to detect and verify gene variants. Bioinformatics tools were used to predict the effects of candidate variants on splicing and protein function. RT-PCR and Sanger sequencing were further performed to validate the impact of the variant on RNA splicing, and homology modeling was applied to predict its effect on the three-dimensional structure of the KIT protein. The pathogenicity of the variant was then classified according to the guidelines of the American College of Medical Genetics and Genomics (ACMG) and the UK Association for Clinical Genomic Science (ACGS). RESULTS: A heterozygous insertion variant near the splice site, c.1990+8_1990+9insTGCACCATTGGAGGTAAA, was identified in the KIT gene in the proband and was found to co-segregate with the phenotype within the family. RT-PCR and cDNA sequencing revealed that this variant led to aberrant splicing during transcription, resulting in a 21 bp in-frame insertion in the mRNA, which encodes an extra 7 amino acids within the tyrosine kinase domain and may thus affect protein function. In silico predictions, together with the experimental findings, supported classification of this variant as likely pathogenic according to relevant variant interpretation guidelines. CONCLUSIONS: The heterozygous splice-site insertion variant KIT:c.1990+8_1990+9insTGCACCATTGGAGGTAAA is the genetic cause of piebaldism in this pedigree.

Genetics diagnosis↗
PubMed2026

[Genetic analysis of a fetus with Short-rib thoracic dysplasia 8 with or without polydactyly due to variants of DYNC2I1 gene].

OBJECTIVE: To investigate the clinical characteristics of a fetus with Short-rib thoracic dysplasia 8 with or without polydactyly (SRTD8) due to variants of DYNC2I1 gene. METHODS: A fetus identified to have short ribs, short long bones, and narrow thorax at 26+1 weeks of gestation at the Women and Children's Hospital of Ningbo University in September 2024 was selected as study subject. The fetus underwent termination of pregnancy at 35+5 weeks of gestation. Clinical data of the fetus were retrospectively collected. Whole exome sequencing (WES) was carried out on fetal tissue, and candidate variants were validated by Sanger sequencing. Difference between the wild type and variant DYNC2I1 proteins was analyzed using AlphaFold v3.0.1 and PyMOL v2.5.6 software. Pathogenicity of the variant was rated based on guidelines from the American College of Medical Genetics and Genomics (ACMG). Using keywords such as "DYNC2I1 gene", previous literature on patients due to biallelic DYNC2I1 gene variants were retrieved from the PubMed databases, CNKI, and Wanfang Data Knowledge Service Platform, and the genetic variant and clinical phenotypes of patients were analyzed. The literature retrieval time was set from the establishment of database to December 31, 2025. This study was approved by the Medical Ethics Committee of the hospital (Ethics No.: 2023-094). RESULTS: Prenatal ultrasound revealed that the fetus had short ribs, short long bones, and narrow thorax at 26+1 gestational weeks. WES and Sanger sequencing revealed that the fetus has harbored compound heterozygous variants of the DYNC2I1 gene, namely c.265_268 (p.Gln89GlyfsTer15) in exon 3 and c.1777C>T (p.Arg593Trp) in exon 14, which were inherited from his father and mother, respectively. Prediction of the DYNC2I1 protein structure suggested that the c.265_268del variant has formed a premature termination codon, which may significantly alter the protein's secondary structure. The c.1777C>T variant may disrupt the electrostatic interaction between Arg593 and Asp729. Based on the ACMG guidelines, the c.265_268del (p.Gln89GlyfsTer15) variant was predicted to be likely pathogenic (PM2_Supporting +PVS1), whilst the c.1777C>T(p.Arg593Trp) variant was rated as uncertain significance (PM2_Supporting+PM3+PP4). Literature search has identified five articles related to biallelic DYNC2I1 variants involving a total of 11 fetuses/patients. Together with the fetus from this study, typical phenotypes included short ribs (6 cases), narrow thorax (6 cases), short limb bones (6 cases), and hand polydactyly (6 cases), and foot polydactyly (5 cases), albeit with significant clinical heterogeneity. A total of 12 genetic variants were identified, among which c.44delC was the most common (16.7%, 4/24), followed by c.1777C>T, c.2246C>T, and c.2305G>A (each accounting for 12.5%). No mutational hotspot was identified. CONCLUSION: The c.265_268del (p.Gln89GlyfsTer15) and c.1777C>T (p.Arg593Trp) compound heterozygous variants of the DYNC2I1 gene probably underlay the pathogenesis of SRTD8 in this fetus. This study has enriched the mutational spectrum of the DYNC2I1 gene and facilitated etiological diagnosis and treatment of DYNC2I1-related diseases.

Humans↗
PubMed2026

[Genetic analysis of a male with Multiple morphological abnormalities of sperm flagella combined with sperm head abnormalities due to compound heterozygous variants of DNAH1 gene and a literature review].

OBJECTIVE: To explore the clinical phenotype and genetic etiology of a male with Multiple morphological abnormalities of sperm flagella (MMAF) combined with sperm head abnormalities due to compound heterozygous variants of DNAH1 gene, with an aim to provide guidance for assisted reproductive technology in his family. METHODS: A man with MMAF combined with sperm head abnormalities who visited Women and Children's Hospital of Ningbo University in October 2024 was selected as study subject. Clinical data of the patient's family were retrospectively collected. Peripheral blood samples were collected from the patient and his spouse, and G-banding karyotyping and whole exome sequencing (WES) were carried out. Candidate variants were validated by Sanger sequencing. Conservation of the DNAH1 protein was queried on the UCSC website. The difference between wild type and variant DNAH1 proteins were analyzed using AlphaFold v3.0.1 and PyMOL v2.5.6. The pathogenicity of variant was rated based on the guidelines from American College of Medical Genetics and Genomics (ACMG). Previous literature was searched using keywords "DNAH1 gene" and "multiple morphological abnormalities of the sperm flagella" on CNKI, Wanfang Data Knowledge Service Platform, and PubMed database to identify cases of MMAF attributed to biallelic DNAH1 gene variants. The retrieval period was set from the establishment of the databases to December 31, 2025. The genotypes and clinical phenotypes of patients with biallelic DNAH1 mutations were analyzed. This study was approved by the Medical Ethics Committee of the hospital (Ethics No.: EC2023-094). RESULTS: The 30-year-old patient and his 30-year-old wife had infertility for 2 years. Semen analysis revealed no motile sperm and a 99.0% abnormal morphology rate. Typical MMAF was observed with phase-contrast microscopy. Sperm morphology analysis revealed abnormalities of the head, neck, and tail with an approximate ratio of 9:5:1. The patient's karyotype was 46,XY, and his wife's karyotype was 45,X[4]/47,XXX[1]/46,XX[84]. WES and Sanger sequencing revealed that the patient harbored compound heterozygous variants of the DNAH1 gene, namely c.1435_1444+3del and c.12204_12206del (p.Asn4069del), but their origin remained unidentified. UCSC genome browser query results showed that the amino acid residue at position 4 069 of the DNAH1 protein is highly conserved across various species. Protein structure prediction reveals that, in the wild-type DNAH1 protein, the Asparagine at position 4 069 (Asn4069) can form hydrogen bonds with the Leucine on the main chain at position 4 086 (Leu4086) and the Serine on the side chain at position 4 087 (Ser4087). The c.12204_12206del variant, resulting in deletion of Asn4069, disrupts these hydrogen bonds and does not generate any compensatory interactions. Based on the ACMG guidelines, the c.1435_1444+3del variant was predicted to be likely pathogenic (PM2_Supporting+PVS1), and the c.12204_12206del(p.Asn4069del) variant was rated as likely pathogenic (PM2_Supporting+PM4+PM3+PP4). The couple had elected for in vitro fertilization using donor sperm. During this cycle, 12 oocytes were retrieved, 10 oocytes were successfully fertilized, 1 embryo and 6 blastocysts were obtained. Following the first transfer of a frozen-thawed blastocyst, implantation of an empty gestational sac occurred, which led to a miscarriage. After the second transfer of a high-quality blastocyst, the embryo split into twins following implantation, and the spouse had selected fetal reduction. The gestational age was 33+3 weeks on June 1, 2026. Literature review identified three studies reporting biallelic mutations of the DNAH1 gene in association with MMAF combined with sperm head abnormalities. Together with the patient from this study, a total of 20 patients were included in the analysis. The rate of sperm flagellar abnormalities in these patients was above 80.0%, while the rate of sperm head abnormalities has ranged from 12.0% to 100.0%. In four patients, the genetic basis was unknown. In the remaining 16 patients, 35 mutations were detected, with c.8626-1G>A being the most common (22.9%, 8/35). CONCLUSION: This patient showed MMAF with frequent sperm head defects. Compound heterozygous variants of the DNAH1 gene probably underlay these abnormalities, which in turn has led to his primary infertility. This study revealed the phenotypic variability of MMAF and broadened the mutational spectrum of the DNAH1 gene.

Humans↗
PubMed2026

[Pathogenicity analysis and prenatal genetic counseling for five Chinese pedigrees harboring a hemizygous c.-32C>G variant of FGF13 gene].

OBJECTIVE: To explore the pathogenicity and prenatal counseling strategies for five Chinese pedigrees harboring a hemizygous c.-32C>G (NM_001139500.2) variant of fibroblast growth factor 13 (FGF13) gene. METHODS: Five Chinese pedigrees found to carry a hemizygous c.-32C>G variant of the FGF13 gene at the Prenatal Diagnosis Center of Henan Provincial People's Hospital between January 2024 and January 2025 were selected as study subjects. The pedigrees had undergone prenatal diagnosis for a family history of genetic disorders, abnormal fetal ultrasound findings, or advanced maternal age. A retrospective analysis was carried out, wherein clinical data for all members of the pedigrees were obtained through the medical records system and outpatient visit system. Peripheral blood samples were collected from all pedigree members, and amniotic fluid samples were obtained from the probands. Following extraction of genomic DNA, prenatal diagnosis was performed using chromosomal microarray analysis (CMA) and trio whole-exome sequencing (trio-WES). Sanger sequencing was used to determine the carrier status for the candidate variant, and Mini-Mental State Examination (MMSE) was used to assess the cognitive function of hemizygous individuals carrying the FGF13 gene c.-32C>G variant. Pathogenicity of candidate variant was assessed based on guidelines from the American College of Medical Genetics and Genomics (ACMG). This study was approved by the Medical Ethics Committee of the hospital (Ethics No.: 2021-171). RESULTS: CMA and trio-WES revealed no pathogenic variants in all probands, whilst trio-WES and Sanger sequencing had identified 11 male individuals carrying a hemizygous c.-32C>G variant of the FGF13 gene from the five pedigrees, which included six adult males, a young boy, and four fetuses. One fetus had undergone termination of pregnancy due to hydrocephalus, one was born pre-term at 34+1 weeks of gestation owing to maternal hypertension, and other two were delivered at full term. Follow-up of the survived males revealed no phenotypic manifestations related to language or intellectual impairment. Among these, three adult males underwent the MMSE assessment, all of whom showed normal cognitive function. Search of the gnomAD database suggested the carrier frequency of FGF13 c.-32C>G variant in the East Asian population to be 0.125%, with 11 hemizygous males documented. Three male patients harboring the variant showed severe intellectual disability. Both in vitro and in vivo studies suggested that it could reduce the translation levels of FGF13 protein. Based on the ACMG guidelines, it was classified as variant of uncertain significance (BS4+PS3_Supporting). CONCLUSION: There is insufficient evidence to classify the FGF13 c.-32C>G as a pathogenic variant in clinical practice, and its presence should not be considered an indication for pregnancy termination due to major birth defects.

Adult↗
PubMed2026

[Study of a patient with azoospermia due to variant of MOV10L1 gene].

OBJECTIVE: To explore the clinical and genotypic characteristics of a patient with Sertoli cell-only syndrome (SCOS) due to variants of MOV10L1 gene. METHODS: A 27-year-old patient with Non-obstructive azoospermia (NOA) underwent routine semen analysis. Serum levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH), progesterone (P), estradiol (E2), prolactin (PRL), and testosterone (T) were determined by chemiluminescence assays. Peripheral blood samples were collected for G-banded karyotyping analysis. Multiplex PCR fluorescence detection was used to screen for AZF gene microdeletions. Whole exome sequencing (WES) and Sanger sequencing were performed simultaneously. Testicular biopsy tissues were subjected to Hematoxylin-Eosin (HE) staining to assess seminiferous tubule cell composition, and MOV10L1 protein expression was detected by immunohistochemical staining. Bioinformatics tools were employed to predict the pathogenicity of variants and their impact on protein structure and function. This study was approved by the Medical Ethics Committee of the Guangdong Institute of Reproductive Sciences [Ethics No.: 2023(01)]. RESULTS: The patient's two semen analyses had failed to detect any sperm. Hormone tests indicated elevated FSH (22.32 mIU/mL) and PRL (397.6 mIU/mL), while T (3.68 nmol/L) and E2 (38.32 pmol/L) were reduced. Chromosomal karyotyping revealed 46,XY, and no AZF gene deletion was detected. WES and Sanger sequencing detected compound heterozygous variants of the MOV10L1 gene, including a c.345C>A (p.C115X) nonsense variant and a c.3323C>T (p.T1108I) missense variant, with the former being unreported previously. HE staining showed only Sertoli cells in the seminiferous tubules, confirming the diagnosis of SCOS. Immunohistochemical staining revealed absent MOV10L1 protein expression in the testicular tissue. Based on the guidelines from American College of Medical Genetics and Genomics (ACMG), the c.345C>A (p.C115X) was classified as a pathogenic variant (PVS1+PM2_Supporting+PP4), while the c.3323C>T (p.T1108I) was deemed variant of uncertain significance (PM2_Supporting+PP3_Supporting+PP4). Bioinformatics analysis demonstrated that c.345C>A (p.C115X) may cause premature termination of protein translation, while c.3323C>T (p.T1108I) may disrupt the hydrophobicity of the RNA helicase domain, reducing the active pocket volume and decreasing its affinity for MILI protein. CONCLUSION: This study has diagnosed a case of SCOS due to compound heterozygous variants of the MOV10L1 gene, which also enriched its mutational spectrum.

Humans↗
PubMed2026

[Analysis of a Chinese pedigree affected with Townes-Brocks syndrome due to a novel variant of SALL1 gene and a literature review].

OBJECTIVE: To analyze a novel exonic variant of the SALL1 gene and its impact on the binding site of SALL protein. METHODS: Clinical data of three children diagnosed with Townes-Brocks syndrome and their family members who had presented at the First Affiliated Hospital of Shandong First Medical University in April 2022 were retrospectively collected. The pathogenic variant was identified through whole-genome sequencing (WGS) and validated by Sanger sequencing. Protein structural prediction was performed using AlphaFold and PyMOL software to construct three-dimensional models of the wild-type and mutant proteins. Additionally, previously reported cases were systematically reviewed. This study was approved by the Medical Ethics Committee of the hospital (Ethics No.: 2023-386). RESULTS: The proband was one of triplet sisters born at 34+4 gestational weeks. All three cases had presented with anal atresia and rectovaginal fistula, and case 3 also had toe malformation of left foot. WGS revealed a novel heterozygous c.757C>T (p.Gln253*) variant in the SALL1 gene, which was predicted to be pathogenic. Sanger sequencing confirmed co-segregation of the variant with the disease within the family. Protein structural modeling demonstrated that the variant has introduced a premature stop codon at position 253, resulting in a truncated protein. CONCLUSION: Above finding has enriched the mutation spectrum of the SALL1 gene in association with Townes-Brocks syndrome, which also represented a rare case of anal atresia in triplets, and provided a basis for molecular diagnosis, genetic counseling, and further research.

Humans↗
PubMed2026

[Genetic and phenotypic analysis of three children with Neurodevelopmental disorders due to variants of DEAF1 gene].

OBJECTIVE: To explore the genetic characteristics and clinical phenotypes of three children with novel DEAF1 gene variants. METHODS: Three children who were referred to Capital Children's Medical Center Affiliated to Capital Medical University between January 2018 and December 2025 were selected as study subjects and underwent whole exome sequencing (WES). Candidate variants were verified by Sanger sequencing, and their pathogenicity was evaluated based on the guidelines from American College of Medical Genetics and Genomics (ACMG). A systematic search of databases including PubMed and CNKI was conducted to compile previously reported cases of DEAF1 variants for clinical phenotype comparison. For the non-canonical splice site variant c.870+5G>C located in the intronic region, wild-type and mutant minigene reporter vectors were constructed and transfected into HeLa and 293T cells, respectively, and the splicing patterns were analyzed by RT-PCR and Sanger sequencing. This study was approved by the Medical Ethics Committee of Capital Institute of Pediatrics (Ethics No.: SHERLL 2020001). RESULTS: All three children were found to have carried de novo heterozygous variants of the DEAF1 gene, including two missense variants (c.764G>A, c.641T>C) in the important SAND domain and a splice site variant (c.870+5G>C) in a non-canonical splicing region. The c.764G>A and c.870+5G>C variants were unreported previously. All children had presented with intellectual developmental delay, and two were accompanied by autism spectrum disorder, and two had epilepsy and sleep disorders. In vitro minigene splicing assay showed that the c.870+5G>C variant can lead to abnormal splicing. CONCLUSIONS: This study reported three children with novel DEAF1 variants, two of which have not been previously described, thereby enriched the mutational spectrum of the DEAF1 gene. In vitro functional assay combined with the clinical manifestations of the patients confirmed the pathogenicity of the non-canonical splice site variant in the intronic region.

Humans↗
PubMedDate not supplied

A conversation with John Sulston.

Sir John Sulston was a co-winner of the Nobel Prize for Medicine in 2002. He won the prize for his discoveries concerning "genetic regulation of organ development and programmed cell death," along with his colleagues sydney Brenner and H. Robert Horvitz. Dr. Sulston was founding director of the Sanger Centre, Cambridge, England, which he headed from 1992 to 2000. From 1993 to 2000, he led the British arm of the international team selected to work on the Human Genome Project. He is co-author of the book The Common Thread: A Story of Science, Politics, Ethics, and the Human Genome, published by Joseph Henry Press in 2002.This interview was conducted on December 20, 2002, shortly after Dr. Sulston was awarded his Nobel Prize and was originally broadcast on that date on radio station WPKN-FM in Bridgeport, Connecticut. The interview was conducted by Valerie Richardson, the Managing Editor of The Yale Journal of Biology and Medicine.Dr. Sulston has been an outspoken advocate against letting the data from the Human Genome Project become property of commercial interests that would charge the world's scientific community for its use. Since leaving the Sanger Institute, he has worked with OxFam, the Oxford Campaign for Famine Relief.

Animals↗
PubMed1981

Sequence analysis of the DNA encoding the Eco RI endonuclease and methylase.

The Eco RI endonuclease and methylase recognize the same hexanucleotide substrate sequence. We have determined the sequence of a fragment of DNA which encodes these enzymes using the chain-termination method of Sanger (Sanger, F., Nicklen, S., and Coulson, A. R. (1977) Proc. Natl. Acad. Sci. U. S. A. 74, 5463-5467). The amino acid sequences of both enzymes were derived from the DNA sequence. The coding regions selected include the only open translational frames of sufficient length to accommodate the enzymes. They coincide with previously established gene boundaries and orientation. The predicted amino acid sequences correlate well with analyses of the purified protein. Comparison of the nucleotide and protein sequences reveals no homology between the endonuclease and methylase which might provide insight into the origin of the restriction-modification system or the mechanism of common substrate recognition. Based on secondary structure predictions, the two enzymes also have grossly different molecular architecture. The base composition of the sequence is 65% A + T, and the codon usage is significantly different from that observed in several Escherichia coli chromosomal genes. In some cases, frequently selected codons are recognized by minor tRNA species. A spontaneous mutation in the endonuclease gene was isolated. Serine replaces arginine at residue 187. In crude extracts, Eco RI specific cleavage is approximately 0.3% wild type.

Amino Acid Sequence↗
PubMed1995

Rapid and efficient screening for p53 gene mutations by dideoxy fingerprinting.

Dideoxy fingerprinting (ddF) is an efficient method for detecting single base and other sequence changes in PCR-amplified DNA segments. This screening method is a hybrid between single-strand conformation polymorphism analysis (SSCP) and Sanger dideoxy sequencing. It involves a Sanger sequencing reaction with one dideoxynucleotide followed by non-denaturing gel electrophoresis. We are using ddF to screen for mutations in the p53 tumor suppressor gene in primary breast cancers. ddF detected more than 100 mutations in different regions of the gene, including all types of single-base mutations and microdeletions/microinsertions of various sizes. Furthermore, ddF reliably detected heterozygous mutations, if the region of interest was screened in both directions. In a blinded, prospective study, ddF detected all 25 mutations within exons 4-10 and adjacent flanking intronic regions previously found by direct sequencing. ddF was also useful in scoring two common polymorphisms within the p53 gene. Guidelines for preventing false-positive and false-negative results are summarized.

Breast Neoplasms↗
PubMed1997

Distribution and orientation of rhodamine-phalloidin bound to thin filaments in skeletal and cardiac myofibrils.

Phalloidin staining of muscle does not reflect the known disposition of sarcomeric thin filaments. Quantitative image analysis and steady-state fluorescence polarization microscopy are used to measure the local intensity and orientation of tetramethyl rhodamine-labeled phalloidin (TR-phalloidin) in skinned myofibrils. TR-phalloidin staining of isolated skeletal myofibrils labeled while in rigor reveals fluorescence that is brighter at the pointed ends of the thin filaments and Z lines than it is in the middle of the filaments. In cardiac myofibrils, phalloidin staining is uniform along the lengths of the thin filaments in both relaxed and rigor myofibrils, except in 0.2-micron dark areas on either side of the Z line. Extraction of myosin or tropomyosin-troponin molecules does not change the nonuniform staining. To test whether long-term storage in glycerol changes the binding of phalloidin to thin filaments in myofibrils, minimally permeabilized (briefly skinned) myofibrils, or myofibrils stored in glycerol for at least 7 days (glycerol extraction) were compared. TR-phalloidin was well ordered throughout the sarcomere in briefly skinned skeletal and cardiac myofibrils, but TR-phalloidin bound to the Z line and pointed ends of thin filaments was randomly oriented in glycerol-extracted myofibrils, suggesting that the ends of the thin filaments become disordered after glycerol extraction. In relaxed skeletal myofibrils with sarcomere lengths greater than 3.0 microns, staining was nearly uniform all along the actin filaments. Exogeneous bare actin filaments polymerized from the Z line (Sanger et al., 1984: J. Cell Biol. 98:825-833) in and along the myofibril bind rhodamine phalloidin uniformly. Our results support the hypothesis that nebulin can block the binding of phalloidin to actin in skeletal myofibrils and nebulette can block phalloidin binding to cardiac thin filaments.

Actin Cytoskeleton↗
PubMed2004

Inhibitors arrest myofibrillogenesis in skeletal muscle cells at early stages of assembly.

A three-step model for myofibrillogenesis has been proposed for the formation of myofibrils [Rhee et al., 1994: Cell Motil. Cytoskeleton 28:1-24; Sanger et al., 2002: Adv. Exp. Med. 481:89-105]: premyofibril to nascent myofibril to mature myofibril. We have found two chemically related inhibitors that will arrest development at both the first and second step. Cultured quail embryonic skeletal myoblasts were treated with ethyl methane sulfonate (EMS) or 2-aminoethyl-methanesulfonate (MTSEA+). When the myoblasts fused in the presence of either of these compounds, myosheets rather than myotubes formed. Treated cells were fixed and immunostained against multiple proteins commonly found in muscle cells. Protein expression and localization throughout the myosheet were similar to that of developing myotube tips. Cells treated with high concentrations of EMS (10 mM) stained for non-muscle myosin II, sarcomeric alpha-actinin, and tropomyosin. No zeugmatin (Z-band region of titin) or muscle myosin II antibody staining was detected in fibers in this treatment group. These fibers are comparable to premyofibrils in control myotubes. At lower concentrations of EMS (7.5 to 5 mM), fibers that formed stained for muscle myosin II and titin as well as for non-muscle myosin IIB, sarcomeric alpha-actinin, and tropomyosin. Muscle myosin II was in an unbanded pattern. These fibers are comparable to nascent myofibrils observed during normal myofibrillogenesis. Similar effects to those obtained by treating cells with EMS were obtained when we treated cultured cells with MTSEA+ (5 mM) and stained them with sarcomeric alpha-actinin. MTSEA+ is chemically related to EMS, and is a well-known inhibitor of ryanodine receptors in skeletal muscle cells. Some abnormalities such as nemaline-like rods and other protein aggregates also appear within the myosheet during EMS and MTSEA+ treatment. Removal of these two inhibitors of myofibrillogenesis allows the premyofibrils and nascent myofibrils to form mature myofibrils.

Animals↗
PubMed1994

Dynamics of actin and alpha-actinin in the tails of Listeria monocytogenes in infected PtK2 cells.

Listeria monocytogenes can penetrate and multiply within a variety of cell types, including the PtK2 kidney epithelial line. Once released within the cytoplasm, L. monocytogenes acquires the capacity for rapid movement through the host cell [Dabiri et al., 1990: Proc. Natl. Acad. Sci. 87:6068-6072]. In the process, actin monomers are inserted in proximity to one end of the bacterium, forming a column or tail of actin filaments [Sanger et al., 1992: Infect. Immun. 60:3609-3619]. The rate of new actin filament growth correlates closely with the speed of bacterial migration. In this study we have used fluorescently labeled actin and alpha-actinin to monitor the movement and turnover rate of actin and alpha-actinin molecules in the tails. The half-lives of the actin and alpha-actinin present in the tails are approximately the same: actin, 58.7 sec; alpha-actinin, 55.3 sec. The half-life of alpha-actinin surrounding a dividing bacterium was 30 sec, whereas its half-life in the tails that formed behind the two daughter cells was about 20-30% longer. We discovered that the speeds of the bacteria are not constant, but show aperiodic episodes of decreased and increased speeds. There is a fluctuation also in the intensities of the fluorescent probes at the bacterium/tail interface, implying that there is a fluctuation in the number of actin filaments forming there. There was no strong correlation, however, between these fluctuating intensities and changes in speed of the bacteria. These measurements suggest that while actin polymerization at the bacterial surface is coupled to the movement of the bacterium, the periodic changes in intracellular motility are not a simple function of the number of actin filaments nucleating at the bacterial surfaces.

Actinin↗
PubMed1993

Equilibrium point control of a monkey arm simulator by a fast learning tree structured artificial neural network.

A planar 17 muscle model of the monkey's arm based on realistic biomechanical measurements was simulated on a Symbolics Lisp Machine. The simulator implements the equilibrium point hypothesis for the control of arm movements. Given initial and final desired positions, it generates a minimum-jerk desired trajectory of the hand and uses the backdriving algorithm to determine an appropriate sequence of motor commands to the muscles (Flash 1987; Mussa-Ivaldi et al. 1991; Dornay 1991b). These motor commands specify a temporal sequence of stable (attractive) equilibrium positions which lead to the desired hand movement. A strong disadvantage of the simulator is that it has no memory of previous computations. Determining the desired trajectory using the minimum-jerk model is instantaneous, but the laborious backdriving algorithm is slow, and can take up to one hour for some trajectories. The complexity of the required computations makes it a poor model for biological motor control. We propose a computationally simpler and more biologically plausible method for control which achieves the benefits of the backdriving algorithm. A fast learning, tree-structured network (Sanger 1991c) was trained to remember the knowledge obtained by the backdriving algorithm. The neural network learned the nonlinear mapping from a 2-dimensional cartesian planar hand position (x,y) to a 17-dimensional motor command space (u1, . . ., u17). Learning 20 training trajectories, each composed of 26 sample points [[x,y], [u1, . . ., u17] took only 20 min on a Sun-4 Sparc workstation. After the learning stage, new, untrained test trajectories as well as the original trajectories of the hand were given to the neural network as input. The network calculated the required motor commands for these movements. The resulting movements were close to the desired ones for both the training and test cases.

Algorithms↗