Assignment of the human GLI2 gene to 2q14 by fluorescence in situ hybridization.
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Chromosome Mapping↗
Biomedical subjects
N Niikawa
Publications and source records attributed to N Niikawa.
Diagnosis of four chromosome abnormalities of unknown origin by chromosome microdissection and subsequent reverse and forward painting.
A molecular cytogenetic method consisting of chromosome microdissection and subsequent reverse/forward chromosome painting is a powerful tool to identify chromosome abnormalities of unknown origin. We present 4 cases of chromosome structural abnormalities whose origins were ascertained by this method. In one MCA/MR patient with an add(5q)chromosome, fluorescence in situ hybridization (FISH), using probes generated from a microdissected additional segment of the add(5q) chromosome and then from a distal region of normal chromosome 5, confirmed that the patient had a tandem duplication for a 5q35-qter segment. Similarly, we ascertained that an additional segment of an add(3p) chromosome in another MCA/MR patient had been derived from a 7q32-qter segment. In a woman with a history of successive spontaneous abortions and with a minute marker chromosome, painting using microdissected probes from the whole marker chromosome revealed that it was i(15)(p10) or psu dic(15;15)(q11;q11). Likewise, a marker observed in a fetus was a ring chromosome derived from the paracentromeric region of chromosome 19. We emphasize the value of the microdissection-based chromosome painting method in the identification of unknown chromosomes, especially for marker chromosomes. The method may contribute to a collection of data among patients with similar or identical chromosome abnormalities, which may lead to a better clinical syndrome delineation.
Abnormalities, Multiple↗
Human ESP1/CRP2, a member of the LIM domain protein family: characterization of the cDNA and assignment of the gene locus to chromosome 14q32.3.
The LIM domain is present in a wide variety of proteins with diverse functions and exhibits characteristic arrangements of Cys and His residues with a novel zinc-binding motif. LIM domain proteins have been implicated in development, cell regulation, and cell structure. A LIM domain protein was identified by screening a human cDNA library with rat cysteine-rich intestinal protein (CRIP) as a probe, under conditions of low stringency. Comparison of the predicted amino acid sequence with several LIM domain proteins revealed 93% of the residues to be identical to rat LIM domain protein, termed ESP1 or CRP2. Thus, the protein is hereafter referred to as human ESP1/CRP2. The cDNA encompasses a 1171-base region, including 26, 624, and 521 bases in the 5'-noncoding region, coding region, and 3'-noncoding regions, respectively, and encodes the entire ESP1/CRP2 of 208 amino acids (M(r), 22,496). Human ESP1/CRP2 protein has two LIM domains, and each shares 35.1% and 77 or 79% identical residues with human cysteine-rich protein (CRP) and rat CRIP, respectively. Northern blot analysis of ESP1/CRP2 in various human tissues showed distinct tissue distributions compared with CRP and CRIP, suggesting that each might serve related but specific roles in tissue organization or function. Using a panel of human-rodent somatic cell hybrids, the ESP1/CRP2 locus was assigned to chromosome 14. Fluorescence in situ hybridization, using cDNA and a genome DNA fragment of the ESP1/CRP2 as probes, confirms this assignment and relegates regional localization to band 14q32.3.
Adaptor Proteins, Signal Transducing↗
Two polymorphic AvaI and HhaI sites in a differentially methylated region of the human H19 gene.
The H19 gene is paternally imprinted both in the human and mouse (Bartolomei et al., 1991; Zhang and Tycko, 1992), although its expression pattern seems somewhat different between the two species (Jinno et al., 1995). DNA-methylation is a promising candidate for a parent-of-origin mark of the gene, and a paternal allele-specific methylation imprint was recently identified at the mouse H19 locus (Tremblay et al., 1995). We found a 50% methylated region in the human H19 gene (Jinno, unpublished data). A search for polymorphisms in this region revealed two novel AvaI and HhaI RFLPs, which contribute to the detection of allele-specific methylation at the human H19 locus.
Alleles↗
Genomic imprinting and its relevance to genetic diseases.
Genomic imprinting is a biological phenomenon determined by an evolutionally acquired, underlying system that may control harmonious development and growth in mammals. It is also relevant to some genetic disorders in man. In this article, lines of biological evidence of imprinting, characteristics of the mouse and human imprinted genes, and findings and mechanisms on the occurrence of several human imprinting disorders are reviewed.
Angelman Syndrome↗
Physical map of a YAC contig containing the region of the human gene (HYRC) complementing hyper-radiosensitivity of the scid mouse mutation.
We previously mapped the putative human HYRC (the hyper-radiosensitivity of the scid mutation, complementing gene) to human chromosome 8q11.1 by fluorescence in situ hybridization (FISH) using Alu-based PCR products from a mouse-human scid radiation cell hybrid (RD15/5) as probes. From a cosmid library constructed from RD15/5, 57 cosmid clones containing human DNA inserts were isolated. 18 of which were mapped to 8q11. Based on the sequences of plasmid subclones of the 18 cosmids, five novel sequence-tagged-sites (STSs) were made. By a screening of the CEPH-YAC library with these STSs, five yeast artificial chromosome (YAC) clones were isolated. All these YAC clones were confirmed not to be chimeric by FISH, but two of them showed deleted human insert DNAs. Using the other 3 non-deleted YACs, we constructed a physical map covering the HYRC region. We confirmed that the recently isolated gene (the DNA-PKcs gene) which is a strong candidate for HYRC is located within the present contig and spans less than 200 kb. This map will be useful for the analysis of the genomic structure of the DNA-PKcs gene and for isolation of other complementing genes in the HYRC region.
Animals↗
A partial hydatidiform mole with 2N/3N mosaicism identified by molecular analysis.
PURPOSE: A placenta with a partial hydatidiform mole was studied using DNA polymorphic markers to determine whether it has a triploid cell line. METHOD: Parent-mole transmission of alleles at 23 polymorphic loci was traced in cells from a molar region and a normal-looking region of the placenta by polymerase chain reaction (PCR) amplification or Southern blot analysis, both followed by densitometric analysis. RESULTS: Allele patterns for 8 of the 23 loci were identical between the DNA from the molar and normal regions of the placenta, while those of the remaining 15 loci were uninformative. In the molar region, the band intensity for the paternally derived allele at each informative locus was always greater than that of the maternally derived allele, the average intensity ratio of the former to the latter being 1.5, whereas the ratio in the normal region was even. CONCLUSIONS: The results suggested that the molar region was a mixoploid consisting of diploid and triploid cells and the phenotypically normal region had a mainly diploid constitution. It is most likely that the placenta may have originated from a single diploid or triploid conceptus, followed by postzygotic gain or loss of a paternal haploid set, and that an extra paternal set contributed to hydropic changes of the placenta.
Diploidy↗
An imprinted gene p57KIP2 is mutated in Beckwith-Wiedemann syndrome.
p57KIP2 is a potent tight-binding inhibitor of several G1 cyclin/Cdk complexes, and is a negative regulator of cell proliferation. The gene encoding p57KIP2 is located at 11p15.5 (ref. 2), a region implicated in both sporadic cancers and Beckwith-Wiedemann syndrome, a cancer-predisposing syndrome, making it a tumour-suppressor candidate. Several types of childhood tumours including Wilms' tumour, adrenocortical carcinoma and rhabdomyosarcoma exhibit a specific loss of maternal 11p15 alleles, suggesting that genomic imprinting is involved. Genetic analysis of the Beckwith-Wiedemann syndrome indicated maternal carriers, as well as suggesting a role of genomic imprinting. Previously, we and others demonstrated that p57KIP2 is imprinted and that only the maternal allele is expressed in both mice and humans. Here we describe p57KIP2 mutations in patients with Beckwith-Wiedemann syndrome. Among nine patients we examined, two were heterozygous for different mutations in this gene-a missense mutation in the Cdk inhibitory domain resulting in loss of most of the protein, and a frameshift resulting in disruption of the QT domain. The missense mutation was transmitted from the patient's carrier mother, indicating that the expressed maternal allele was mutant and that the repressed paternal allele was normal. Consequently, little or no active p57KIP2 should exist and this probably causes the overgrowth in this BWS patient.
Beckwith-Wiedemann Syndrome↗
Genomic imprinting of human p57KIP2 and its reduced expression in Wilms' tumors.
p57KIP2 is a potent tight-binding inhibitor of several G1 cyclin complexes, and is a negative regulator of cell proliferation. The gene encoding human p57KIP2 is located on chromosome 11p15.5, a region implicated in both sporadic cancers and Beckwith-Wiedemann syndrome (BWS), a cancer syndrome, making it a tumor suppressor candidate. Several types of childhood tumors including Wilms' tumor, adrenocortical carcinoma and rhabdomyosarcoma display a specific loss of maternal 11p15 alleles, suggesting that genomic imprinting plays an important part. Genetic analysis of the familial BWS has indicated maternal carriers and suggested a role in genomic imprinting. Previously, we demonstrated that p57KIP2 is imprinted in the mouse. Here we describe the genomic imprinting of human p57KIP2 and the reduction of its expression in Wilms' tumors. High resolution mapping locates p57KIP2 in the region responsible for both tumor suppressivity and BWS.
Alleles↗
Mouse/human sequence divergence in a region with a paternal-specific methylation imprint at the human H19 locus.
We have identified a region with characteristics of a paternal-specific methylation imprint at the human H19 locus. This region, extending from -2.0 kb upstream to the start of transcription, is heavily methylated in sperm and on the paternal allele in somatic cells. This methylation was preserved during pre-implantation. Structural analysis revealed the presence of CpG islands and a large direct repeat with a 400 bp sequence reiterated several times, but no significant sequence homology to the corresponding region of the mouse H19 gene. These findings could suggest a role for secondary DNA structure in genomic imprinting across the species, and they also present a puzzling aspect of the evolution of the H19 regulatory region in human and mouse.
Alleles↗
Trisomy 13/trisomy 18 mosaicism in an infant.
Cytogenetic analysis of amniotic fluid cells from a 31-week-old fetus suffering from polyhydramnios revealed that there were two cell lines, each with either trisomy 13 or trisomy 18. We studied the origin and mechanism for formation of this unique mixoploidy by tracing chromosomal heteromorphisms as genetic markers, and showed no discordance of parent-child transmission between the two cell lines in any of the heteromorphisms examined. The result indicated that the mixoploidy is not chimerism but mosaicism and that the mechanism of mosaic development is most likely due to two non-disjunctional events which had occurred independently at the two-cell stage of the zygote. A girl was born at the 38th gestational week and her clinical features were mainly those for trisomy 13. Chromosome analysis of the newborn confirmed +13/+18 mosaicism in fibroblasts from the skin and chorionic plate, while cord blood lymphocytes and chorionic villus cells showed only the +18 cell line.
Abnormalities, Multiple↗
The human HCLS1 gene maps to chromosome 3q13 by fluorescence in situ hybridization.
The human HS1 gene (HCLS1, hematopoietic cell-specific Lyn substrate 1) expressed in human hematopoietic cells encodes a major substrate of protein-tyrosine kinase, p75HS1. This intracellular protein is involved in the signal transduction pathways that initiate at the antigen receptors of both B and T lymphocytes. Fluorescence in situ hybridization using a 2.0-kb cDNA and an 8.0-kb genomic DNA clone of HCLS1 as probes revealed that the gene maps to 3q13.
Adaptor Proteins, Signal Transducing↗
Assignment of the human beta-microseminoprotein gene (MSMB) to chromosome 10q11.2.
Beta-microseminoprotein (MSP) is one of the major proteins secreted by the prostate, and its biological role in tumorigenesis of the prostate has been postulated. We assigned the human MSP gene (MSMB) to 10q11.2 with fluorescence in situ hybridization using a phage clone that has an MSP gene insert. Our mapping data shows that the gene is outside the previously identified LOH-regions (10p and 10q24-->qter) in prostate cancer cells and indicates that MSMB can be ruled out as a candidate for a tumor suppressor gene localized to those regions.
Base Sequence↗
The human gene encoding the heavy chain of the major histocompatibility complex class I-like Fc receptor (FCGRT) maps to 19q13.3.
FcRn is an Fc receptor that structurally resembles the major histocompatibility complex class I molecule. In this study, we isolated the human gene encoding the heavy chain of FcRn (FCGRT) and mapped it by fluorescence in situ hybridization to chromosome band 19q13.3. Thus, like its mouse counterpart, the human FCGRT gene is located outside the major histocompatibility complex.
Animals↗
Genomic cloning and localization to chromosome 11p15.5 of the human achaete-scute homolog 2 (ASCL2).
The mouse achaete-scute homolog-2 gene (Mash2), a member of the achaete-scute gene family, encodes a transcription factor that plays an important role in the development of the trophoblast. It has recently been reported that Mash2 is genomically imprinted and mapped to the distal region of mouse chromosome 7, where other imprinted genes, Ins2, Igf2 and H19 are located. We isolated a clone carrying the partial human homolog, ASCL2, from a human genomic phage library using a PCR product for the rat Ascl2-cDNA as a probe. By fluorescence in situ hybridization using a phage clone as a probe whose insert contained the partial human ASCL2, we assigned ASCL2 to human chromosome 11p15.5. Sequence comparisons of the human ASCL2 clone and the rat Ascl2-cDNA showed 86.9% identity spanning 206 nucleotides and 85.3% deduced polypeptide-sequence identity over 68 residues.
Amino Acid Sequence↗
Isolation of a cosmid clone corresponding to an inv(21) breakpoint of a patient with transient abnormal myelopoiesis.
Transient abnormal myelopoiesis (TAM) is a leukemoid reaction occurring occasionally on Down syndrome (DS) newborn infants. It has been hypothesized that "disomic homozygosity" in 21-trisomic cells plays an important role in the genesis of TAM, and the putative TAM gene was suggested to be mapped at a 21q11 region. We encountered a DS-associated TAM infant with a 47,XY,inv(21)(q11.1q22.13),+inv(21)(q11.1q22.13) karyotype. On the basis of another presumption that in this patient the putative TAM gene is disrupted by the break, we tried to isolate a breakpoint DNA. FISH analysis with cosmid clones corresponding to various sequence-tagged-site (STS) markers mapped at around 21q11.1-q11.2, we confirmed that the proximal breakpoint of the inv(21) was located between two STSs, G51E07 and D21S215, the latter locus being consistent with the previous tentative mapping. After construction of a cosmid contig encompassing between the two markers, we have isolated a cosmid clone corresponding to the proximal breakpoint of the inversion. This breakpoint was located near a previously identified duplicated region that is homologous to the sequence at 21q22.1. The isolated cosmid clone is useful for analysis of other TAM patients and for a search for a transcript at or flanking the breakpoint.
Adult↗
[Positional cloning of the putative gene responsible for transient abnormal myelopoiesis and that for multiple cartilaginous exostoses].
Positional cloning of the putative gene responsible for transient abnormal myelopoiesis (TAM) and that for multiple cartilaginous exostoses (MEX) is described. TAM is a leukemoid reaction occurring frequently in Down syndrome (DS) newborn infants and they often develop true leukemia several years later. The previous findings of "disomic homozygosity in trisomic cells" and tentative mapping of the TAM gene to 21q11.1, and an encounter of a unique DS-associated TAM patient with inv(21) (q11.1q22.13) let us start positional cloning of the TAM gene. One type of MEX is an autosomal dominant disorder and patients with MEX sometimes develop chondrosarcoma. The MEX gene has been mapped to 8q24. We encountered a sporadic case of MEX with de novo t(8q; 13q). Thus, we hypothesized that in both patients, the TAM and the MEX genes are disrupted by the structural chromosome abnormalities. For TAM, we first mapped the proximal breakpoint of inv(21) between 2 STSs using 7 cosmid clones as FISH probes that were isolated on the basis of STS markers at the 21q11.1 region, isolated their corresponding YACs, and then analyzed them. However, since YACs corresponding to 2 other STSs between the two markers could not be isolated, we carried out a chromosome walking to construct a cosmid contig between the 2 STSs. Southern analysis with a cosmid clone within the contig detected EcoRI-/HindIII extra bands on the patient's DNA. The cDNA screening and exon trapping to isolate a gene from the region are underway. Similarly, in the MEX patient we mapped the 8q breakpoint between 2 cosmid markers, then isolated YACs and cosmid subclones. By exon trapping after detection of a cosmid covering the breakpoint, an exon-like sequence was isolated. The 3'-RACE/5'-RACE revealed a novel transcript from this cosmid. Whether the transcript is the MEX gene remains to be determined.
Chromosome Mapping↗
[Genomic imprinting].
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Angelman Syndrome↗