Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Genomic sequencing”

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 1,243 records · Page 69Linked to original sources
PubMed1995

Genomic sequencing indicates a correlation between DNA hypomethylation in the 5' region of the pS2 gene and its expression in human breast cancer cell lines.

The methylation status of the cytosines located on the 5' region of the pS2 gene have been investigated in two human breast cancer cell lines. The genomic sequencing method used is based on an oxydative deamination by NaHSO3 of the unmethylated cytosines, but not 5-methylcytosine. Data obtained indicate that in the DNA extracted from the pS2-expressing cell line, MCF7, the CpG located at the 5' flanking sequence of pS2 are unmethylated. In contrast in the non-expressing cell line, BT20, these CpG are largely methylated. However, this correlation is not observed at all CpG sites, since a significant portion of the cloned PCR fragments obtained from BT20 cells are unmethylated at specific CpG sites. These results suggest that the methylation status of only some of the CpG located at the 5' flanking sequences of pS2 might differ between expressing and nonexpressing cell lines.

Base Sequence↗
PubMed2000

Complete genomic sequence of a dengue type 2 virus from the French West Indies.

Severe forms of dengue fever, dengue haemorrhagic fever, and dengue shock syndrome, were not prominent in the Americas until the epidemic of Cuba in 1981. Since that time, they have spread to other countries in Central and South America, correlating with the spread of dengue type 2 viruses related to Southeast Asian strains. We report here the complete genomic sequence of a dengue type 2 virus isolated during the epidemic in La Martinique in 1998. This constitutes the first complete genetic characterization of a dengue virus strain from French West Indies, and also the first molecular identification in this region of a dengue 2 strain phylogenetically related to the emerging American type 2 dengue viruses.

Amino Acid Substitution↗
PubMed2003

Complete genome sequences of the SARS-CoV: the BJ Group (Isolates BJ01-BJ04).

Beijing has been one of the epicenters attacked most severely by the SARS-CoV (severe acute respiratory syndrome-associated coronavirus) since the first patient was diagnosed in one of the city's hospitals. We now report complete genome sequences of the BJ Group, including four isolates (Isolates BJ01, BJ02, BJ03, and BJ04) of the SARS-CoV. It is remarkable that all members of the BJ Group share a common haplotype, consisting of seven loci that differentiate the group from other isolates published to date. Among 42 substitutions uniquely identified from the BJ group, 32 are non-synonymous changes at the amino acid level. Rooted phylogenetic trees, proposed on the basis of haplotypes and other sequence variations of SARS-CoV isolates from Canada, USA, Singapore, and China, gave rise to different paradigms but positioned the BJ Group, together with the newly discovered GD01 (GD-Ins29) in the same clade, followed by the H-U Group (from Hong Kong to USA) and the H-T Group (from Hong Kong to Toronto), leaving the SP Group (Singapore) more distant. This result appears to suggest a possible transmission path from Guangdong to Beijing/Hong Kong, then to other countries and regions.

Genome, Viral↗
PubMed2001

Genome sequence of bovine herpesvirus 4, a bovine Rhadinovirus, and identification of an origin of DNA replication.

Bovine herpesvirus 4 (BoHV-4) is a gammaherpesvirus of cattle. The complete long unique coding region (LUR) of BoHV-4 strain 66-p-347 was determined by a shotgun approach. Together with the previously published noncoding terminal repeats, the entire genome sequence of BoHV-4 is now available. The LUR consists of 108,873 bp with an overall G+C content of 41.4%. At least 79 open reading frames (ORFs) are present in this coding region, 17 of them unique to BoHV-4. In contrast to herpesvirus saimiri and human herpesvirus 8, BoHV-4 has a reduced set of ORFs homologous to cellular genes. Gene arrangement as well as phylogenetic analysis confirmed that BoHV-4 is a member of the genus Rhadinovirus. In addition, an origin of replication (ori) in the genome of BoHV-4 was identified by DpnI assays. A minimum of 1.69 kbp located between ORFs 69 and 71 was sufficient to act as a cis signal for replication.

Animals↗
PubMed1990

General colorimetric method for DNA diagnostics allowing direct solid-phase genomic sequencing of the positive samples.

A system for rapid colorimetric detection of specific genome DNA fragments amplified by the polymerase chain reaction (PCR) is described that has been designed to allow direct solid-phase sequencing of positive samples. The amplified material is immobilized on magnetic beads by using the biotin streptavidin system. An Escherichia coli lac operator DNA sequence is incorporated in the amplified material during the second step of a nested primer procedure. This 21-base-pair sequence is used for a general colorimetric detection with a fusion protein consisting of the E. coli Lac repressor and beta-galactosidase. Positive samples can be treated subsequently with alkali to obtain a single-stranded DNA template suitable for direct genomic sequencing. This method to detect immobilized amplified nucleic acids (DIANA) is well adapted for automated or semiautomated clinical assays. Here, we show that it can be used to detect and sequence Chlamydia trachomatis genomic DNA in clinical samples.

Amino Acid Sequence↗
PubMed1993

Structure and genomic sequence of the myotonic dystrophy (DM kinase) gene.

The mutation causing myotonic dystrophy (DM) has recently been identified as an unstable CTG trinucleotide repeat located in the 3' untranslated region of a gene encoding for a protein with putative serine-threonine protein kinase activity. In this report we present the genomic sequences of the human and murine DM kinase gene. A comparison of these sequences with each other and with known cDNA sequences from both species, led us to predict a translation initiation codon, as well as determine the organization of the DM kinase gene. Several polymorphisms within the human DM kinase gene have been identified, and PCR assays to detect two of these are described. The complete sequence and characterization of the structure of the DM kinase gene, as well as the identification of novel polymorphisms within the gene, represent an important step in a further understanding of the genetics of myotonic dystrophy and the molecular biology of the gene.

Animals↗
PubMedDate not supplied

Extrachromosomal circular DNAs and genomic sequence plasticity in eukaryotic cells.

The ability of eukaryotic organisms of the same genotype to vary in developmental pattern or in phenotype according to varying environmental conditions is frequently associated with changes in extrachromosomal circular DNA (eccDNA) sequences. Although variable in size, sequence complexity, and copy number, the best characterized of these eccDNAs contain sequences homologous to chromosomal DNA which indicates that they might arise from genetic rearrangements, such as homologous recombination. The abundance of repetitive sequence families in eccDNAs is consistent with the notion that tandem repeats and dispersed repetitive elements participate in intrachromosomal recombination events. There is also evidence that a fraction of this DNA has characteristics similar to retrotransposons. It has been suggested that eccDNAs could reflect altered patterns of gene expression or an instability of chromosomal sequences during development and aging. This article reviews some of the findings and concepts regarding eccDNAs and sequence plasticity in eukaryotic genomes.

Animals↗
PubMed2000

Tuberculosis vaccine design: influence of the completed genome sequence.

Tuberculosis continues to be a major health problem, with more adults dying from Mycobacterium tuberculosis than any other pathogen world-wide. With the onset of the HIV epidemic and an increase in drug-resistant M. tuberculosis strains, the need for an improved vaccine has become an international priority. The recent completion of the genome sequences for two M. tuberculosis strains provides a wealth of information that can be used to design new strategies for vaccine development. The challenge comes in making rational choices from among the 4,000 genes of the most probable candidate immunogens or virulence genes.Thus, a well-designed screen is needed to reduce the number of candidates that must be tested. Presently, the most valuable role that bioinformatics can play is to provide such a screen.

Animals↗
PubMed2004

Illuminating autoimmune regulators through controlled variation of the mouse genome sequence.

Gene variants in mice that have strong, Mendelian effects on autoimmune susceptibility have been one of the most productive entry points for identifying genes and processes regulating human autoimmunity. With the tools now available to map and identify new mouse Mendelian gene variants, the handful of spontaneous mutations accumulated over several decades have all been identified, and the main bottleneck lies in producing new Mendelian immune variants. We outline here a strategy to generate large sets of functional variants in genes controlling lupus and humoral immunity, based upon limited variation of the mouse genome sequence with the chemical mutagen, ENU, combined with a set of sensitive immunological screens.

Animals↗
PubMed1992

PCR-aided genomic sequencing of 5' subterminal sequences of the maize transposable element Activator (Ac) in transgenic tobacco plants.

The maize transposable element Activator (Ac) carries subterminal CpG-rich sequences which are essential for the transposition of the element. It has previously been shown that the methylation of certain sequences contained in this region can alter their ability to interact with the Ac-encoded protein. The novel hypothesis that the methylation of subterminal Ac sequences is required for transposition was tested. Approximately 150 bp of the 5' subterminal region of the Ac element was examined for the presence of 5-methylcytosines by the ligation-mediated polymerase chain reaction (LMPCR)-aided genomic sequencing method. The methylation status of 22 and 39 cytosines on either strand of the DNA were analysed in each of five different transgenic tobacco cultures carrying transposable Ac sequences. Ten micrograms of tobacco DNA were used for each base-specific cleavage reaction before amplification by LMPCR. All but one of the cytosines were unmethylated. Only a minor fraction of the Ac molecules was methylated at one cytosine residue. It is concluded that DNA methylation at the tested Ac sequences is not required for the transposability of Ac or Ds elements in tobacco cells.

Base Sequence↗
PubMed2026

Large-scale whole-genome sequencing reveals the landscape and health implications of de novo mutations.

De novo mutations (DNMs) are an important source of congenital diseases. With delayed parenthood and assisted reproductive technology (ART) use increasing, it is essential to elucidate how these reproductive factors influence DNMs and whether resulting mutations influence offspring health. Here we performed whole-genome sequencing of 24,030 individuals from 7,851 parent-offspring families, identifying 390,924 de novo single-nucleotide variants (dnSNVs). Paternal and maternal aging exhibited distinct mutational patterns, with maternal DNM accumulation accelerating at advanced ages. Increased paternal dnSNVs partially accounted for the association between advanced parental age and shorter gestational duration. Moreover, ART showed age-independent, procedure-specific effects: intracytoplasmic sperm injection (ICSI) and ovarian stimulation were associated with increased paternal and maternal dnSNVs, respectively, and ICSI-associated paternal dnSNVs also partially accounted for the association between ICSI and shorter gestational duration. In vitro embryo manipulation was associated with increased early post-zygotic mosaic mutations, particularly C > A substitutions linked to delayed neurocognitive development at 1 year. Collectively, these findings advance understanding of the determinants and consequences of de novo mutagenesis.

Journal Article↗
PubMed1990

Study of the Alzheimer's A4 precursor gene promoter region by genomic sequencing using Taq polymerase.

The beta-amyloid protein has been identified as the prominent component of the fibrillary aggregates of the neuritic plaques found in Alzheimer's disease (AD). In this paper, the DNA methylation pattern of the promoter region of the Alzheimer's disease amyloid precursor gene (PAD) was assessed using the recently developed genomic sequencing technique with Taq polymerase. We analyzed seven potential methylation sites between position -460 and -275 of the PAD promoter. Three of the CpG dinucleotides we analyzed are located in the flanking regions of the AP-1 binding site and heat-shock response element consensus sequences. Of the seven CpG dinucleotides present in this region, we found none to be methylated. This finding indicates that, in healthy brain tissue, cytosine methylation of this binding motif seems not to affect protein/DNA interaction. However, it remains to be determined whether methylation of these sites is significant in AD patients.

Alzheimer Disease↗
PubMed1997

Detection of pseudorabies virus genomic sequences in apparently uninfected 'single reactor' pigs.

With a pseudorabies virus (PrV) gB ELISA, performed on 480,000 pigs on 8,900 Swedish farms, approximately 1,300 cases were observed with only one single animal reacting positively. These animals were termed 'single reactors' (SR). In order to find explanations for this peculiar phenomenon, the presence of PrV was investigated in organs of immunosuppressed and non-immunosuppressed SR animals. The virus was not detected by immunohistochemistry, virus isolation or co-cultivation. An in situ DNA hybridization test detected PrV gC gene sequences in the olfactory bulb of one sow. A nested polymerase chain reaction (PCR) assay revealed gB, gE and gD gene sequences of PrV in the tissues of trigeminal ganglia, olfactory bulb, tonsils and brain. The nucleotide sequences of the amplicons revealed 98 to 100% homology with the corresponding sequences of PrV. The large latency transcript (LLT) was not detected in the organs of the SR pigs. Transmission of the SR phenomenon to animals in contact or to the next generation was not observed. Considering the present observations and the facts that (i) PrV vaccination is not applied in Sweden; (ii) the SR animals occur not only in the South, but also in Northern Scandinavia, which has no history of PrV infection and (iii) viral reactivation was not observed under natural conditions or after experimental immunosuppression, it is concluded that the SR phenomenon should hardly be considered as a typical PrV latency. The present findings show that certain herpesviral genomic sequences exist in apparently uninfected individuals.

Animals↗
PubMed1990

In vivo footprint and methylation analysis by PCR-aided genomic sequencing: comparison of active and inactive X chromosomal DNA at the CpG island and promoter of human PGK-1.

The promoter region of the X-linked human phosphoglycerate kinase-1 (PGK-1) gene is a CpG island, similar to those often found near autosomal genes. We used ligation-mediated polymerase chain reaction (PCR) for a genomic sequencing study in which 450 bp of the human PGK-1 promoter region was analyzed for the presence of in vivo protein footprints and cytosine methylation at all CpG sites. A technique was devised to selectively visualize the DNA of the inactive X chromosome (Xi), even in the presence of the active X chromosome (Xa). We found that the human Xa in both normal male lymphocytes and hamster-human hybrids is completely unmethylated at all 120 CpG sites. In contrast, 118 of the CpG sites are methylated on the human Xi in hamster-human hybrids. The Xi in normal female lymphocytes is also highly methylated, but some GCG or CGC trinucleotides partially escape methylation; all other CpGs are fully methylated. In vivo footprinting studies with dimethylsulfate (DMS) revealed eight regions of apparent protein-DNA contacts on the Xa. Four of the footprints contained the consensus sequence of the binding site for transcription factor Sp1. The other regions include potential binding sites for transcription factors ATF, NF1, and a CCAAT-binding protein. The Xi did not show any specifically protected sequences, and with the exception of four hyperreactive sites, the in vivo DMS reactivity profile of Xi DNA was very similar to that of purified, linear Xi DNA. The implications of these findings with regard to the maintenance of methylation-free islands, X chromosome inactivation, and the chromatin structure of facultative heterochromatin are discussed.

Animals↗
PubMed1984

Genomic sequencing.

Unique DNA sequences can be determined directly from mouse genomic DNA. A denaturing gel separates by size mixtures of unlabeled DNA fragments from complete restriction and partial chemical cleavages of the entire genome. These lanes of DNA are transferred and UV-crosslinked to nylon membranes. Hybridization with a short 32P-labeled single-stranded probe produces the image of a DNA sequence "ladder" extending from the 3' or 5' end of one restriction site in the genome. Numerous different sequences can be obtained from a single membrane by reprobing. Each band in these sequences represents 3 fg of DNA complementary to the probe. Sequence data from mouse immunoglobulin heavy chain genes from several cell types are presented. The genomic sequencing procedures are applicable to the analysis of genetic polymorphisms, DNA methylation at deoxycytidines, and nucleic acid-protein interactions at single nucleotide resolution.

Animals↗
PubMed1994

Requirement of the 5'-end genomic sequence as an upstream cis-acting element for coronavirus subgenomic mRNA transcription.

We have developed a defective interfering (DI) RNA containing a chloramphenicol acetyltransferase reporter gene, placed behind an intergenic sequence, for studying subgenomic mRNA transcription of mouse hepatitis virus (MHV), a prototype coronavirus. Using this system, we have identified the sequence requirement for MHV subgenomic mRNA transcription. We show that this sequence requirement differs from that for RNA replication. In addition to the previously identified requirement for an intergenic (promoter) sequence, additional sequences from the 5' end of genomic RNA are required for subgenomic mRNA transcription. These upstream sequences include the leader RNA and a spacer sequence between the leader and intergenic sequence, which is derived from the 5' untranslated region and part of gene 1. The spacer sequence requirement is specific, since only the sequence derived from the 5' end of RNA genome, but not from other MHV genomic regions or heterologous sequences, could initiate subgenomic transcription from the intergenic sequence. These results strongly suggest that the wild-type viral subgenomic mRNAs (mRNA2 to mRNA7) and probably their counterpart subgenomic negative-sense RNAs cannot be utilized for mRNA amplification. Furthermore, we have demonstrated that a partial leader sequence present at the 5' end of genome, which lacks the leader-mRNA fusion sequence, could still support subgenomic mRNA transcription. In this case, the leader sequences of the subgenomic transcripts were derived exclusively from the wild-type helper virus, indicating that the MHV leader RNA initiates in trans subgenomic mRNA transcription. Thus, the leader sequence can enhance subgenomic transcription even when it cannot serve as a primer for mRNA synthesis. These results taken together suggest that the 5'-end leader sequence of MHV not only provides a trans-acting primer for mRNA initiation but also serves as a cis-acting element required for the transcription of subgenomic mRNAs. The identification of an upstream cis-acting element for MHV subgenomic mRNA synthesis defines a novel sequence requirement for regulating mRNA synthesis in RNA viruses.

Animals↗
PubMed2001

Complete genomic sequence of the filamentous nitrogen-fixing cyanobacterium Anabaena sp. strain PCC 7120.

The nucleotide sequence of the entire genome of a filamentous cyanobacterium, Anabaena sp. strain PCC 7120, was determined. The genome of Anabaena consisted of a single chromosome (6,413,771 bp) and six plasmids, designated pCC7120alpha (408,101 bp), pCC7120beta (186,614 bp), pCC7120gamma (101,965 bp), pCC7120delta (55,414 bp), pCC7120epsilon (40,340 bp), and pCC7120zeta (5,584 bp). The chromosome bears 5368 potential protein-encoding genes, four sets of rRNA genes, 48 tRNA genes representing 42 tRNA species, and 4 genes for small structural RNAs. The predicted products of 45% of the potential protein-encoding genes showed sequence similarity to known and predicted proteins of known function, and 27% to translated products of hypothetical genes. The remaining 28% lacked significant similarity to genes for known and predicted proteins in the public DNA databases. More than 60 genes involved in various processes of heterocyst formation and nitrogen fixation were assigned to the chromosome based on their similarity to the reported genes. One hundred and ninety-five genes coding for components of two-component signal transduction systems, nearly 2.5 times as many as those in Synechocystis sp. PCC 6803, were identified on the chromosome. Only 37% of the Anabaena genes showed significant sequence similarity to those of Synechocystis, indicating a high degree of divergence of the gene information between the two cyanobacterial strains.

Anabaena↗