Three polymorphisms at the D10S85 locus.
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Chromosome Mapping↗
Biomedical subjects
P J Goodfellow
Publications and source records attributed to P J Goodfellow.
Generation of a panel of somatic cell hybrids containing unselected fragments of human chromosome 10 by X-ray irradiation and cell fusion: application to isolating the MEN2A region in hybrid cells.
We have used X-ray irradiation and cell fusion to generate somatic cell hybrids containing fragments of human chromosome 10. Our experiments were directed towards isolating the region of the MEN2A gene in hybrids and to use those as the source of DNA for cloning and mapping new markers from near the MEN2A locus. A number of hybrid clones containing human sequences that are tightly linked to the MEN2A gene were identified. Some 25% of our hybrids, however, proved to contain more than one human chromosome 10-derived fragment or showed evidence of deletions and/or rearrangements. A detailed analysis of the human content of X-ray irradiation hybrids is required to assess the integrity and number of human fragments retained. Despite retention of multiple human-derived fragments, these hybrids will prove useful as cloning and mapping resources.
Animals↗
Rapid cloning and characterization of new chromosome 10 DNA markers by Alu element-mediated PCR.
Alu element-mediated polymerase chain reaction is a strategy for rapidly cloning and mapping human DNA markers from mixed DNA sources. A novel primer homologous to the 3' end of the human Alu repeat element provides the basis for preferential synthesis of human DNA fragments from human/rodent somatic cell hybrid DNA template. This approach has been used to isolate a series of new markers from chromosome 10. The Alu element-mediated PCR probes were regionally assigned on chromosome 10 by hybridization to Southern blots of Alu PCR-synthesized DNA derived from somatic cell hybrid template DNA. Alu element-mediated PCR is generally applicable and makes possible the analysis of complex genomes with a speed and sensitivity that has not been previously possible.
Animals↗
A new DNA marker (D10S94) very tightly linked to the multiple endocrine neoplasia type 2A (MEN2A) locus.
Combined somatic cell hybrid and linkage studies between D10S94 and five pericentromeric loci (FNRB, D10Z1, MEN2A, RBP3, and D10S15) have localized the new DNA sequence pcl1/A1S-6-c23 at D10S94 to 10q11.2. No recombinants were observed between D10S94 and D10Z1 or MEN2A. D10S94 maps in proximal 10q11.2 very near to MEN2A. There are three possible orders for the six loci that we investigated from the centromeric region of chromosome 10. At present the genetic data do not allow us to order MEN2A with respect to D10Z1 and D10S94. The three possible orders are FNRB-D10Z1-D10S94-MEN2A-RBP3-D10S15, FNRB-D10Z1-MEN2A-D10S94-RBP3-D10S15, and FNRB-MEN2A-D10Z1-D10S94-RBP3-D10S15. In view of the fact that no recombinants between D10S94 and MEN2A or between D10S94 and D10Z1 were observed, the combined haplotypes formed from RFLPs and D10Z1 and D10S94 will increase the informativeness and accuracy of genotype prediction for at-risk members of the families having the MEN 2A syndrome, particularly when the affected parent is female. The localization of D10S94 with respect to MEN2A will prove valuable in experiments directed toward cloning the MEN2A locus.
Adrenal Gland Neoplasms↗
Strong linkage disequilibrium between the XY274 polymorphism and the pseudoautosomal boundary.
The pseudoautosomal boundary is defined by an Alu repeat element on the Y chromosome. The Alu element is found on all Y chromosomes and on no X chromosomes, establishing it as part of Y-specific sequences. Distal to the Alu element, sequences from the X and Y are strictly homologous, suggesting that the boundary is formed by an abrupt break in sequence homology. Further investigation of the function of the boundary has been undertaken by examining the population structure of an MspI restriction-site polymorphism (XY274), which is located 274 bp distal to the Alu insertion site. Southern blot and polymerase chain reaction analysis demonstrate fixation of the high allele (noncutting or AT base pair) of XY274 on the Y chromosome in most populations, while a full range of high allele frequencies is found on the X chromosomes of different populations. Two exceptions to fixation on the Y chromosome were found in African populations. The level of linkage disequilibrium suggests that the first few hundred base pairs of the pseudoautosomal region on the Y chromosome share a single common origin more recent than the origin of the species.
Base Sequence↗
The pseudoautosomal boundary in man is defined by an Alu repeat sequence inserted on the Y chromosome.
The Y chromosome, which in man determines the male sex, is composed of two functionally distinct regions. The pseudoautosomal region is shared between the X and Y chromosome and is probably required for the correct segregation of the sex chromosomes during male meiosis. The second region includes the sex-determining gene(s), the presence of which is necessary for the development of testes. The two regions have contrasting genetic properties: the pseudoautosomal region recombines between the X and Y chromosome; the Y-specific region must avoid recombination otherwise the chromosomal basis of sex-determination breaks down. The pseudoautosomal region is bounded at the distal end by the telomere and at the proximal end by X- and Y-specific DNA. We have found that the proximal boundary was formed by the insertion of an Alu sequence on the Y chromosome early in the primate lineage. Proximal to the Alu insertion there is a small region where similarity between the X and Y chromosomes is reduced and which is no longer subject to recombination.
Base Sequence↗
The beta subunit locus of the human fibronectin receptor: DNA restriction fragment length polymorphism and linkage mapping studies.
The beta subunit of the human fibronectin receptor (FNRB) is a transmembrane protein belonging to the VLA (very late antigens of activation) family. Using pGEM-32, a 2.5-kb partial cDNA clone corresponding to the 3' portion of the human FNRB locus, multiple restriction fragment length polymorphisms (RFLPs) were revealed on DNAs from unrelated Caucasians. RFLPs detected by five enzymes, BanII, HinfI, KpnI, BglII, and SacI, are of the simple two-allele form, and pairwise linkage analyses of these RFLPs with numerous known DNA markers from the chromosome-10 pericentromeric region not only confirmed the chromosome-10 assignment of the functional FNRB gene but also supported its localization at p11.2 suggested by in situ hybridization. An infrequent MspI RFLP was detected by pB/R2, a 4.6-kb genomic clone from the FNRB locus. Another type of DNA polymorphism was also revealed by the cDNA clone and it was visualized on the Southern blot analyses as the presence or absence of an extra band (or a set of extra bands). It seems to stem from a stretch of DNA sequence present in some individuals at one single locus but absent in others, and is of non-chromosome-10 origin based on linkage analyses with known chromosome 10 markers. This "presence/absence" type of polymorphism could be revealed by all of the 25 restriction enzymes tested and is similar in nature to that previously reported with one of the human dihydrofolate reductase pseudogenes, DHFRP1. Dissection of the pGEM-32 clone demonstrated that the region revealing the non-chromosome-10 sequences is within a fragment about 1.7 kb in length extending from about 600 nucleotides preceding the stop codon down to the end of the cloned FNRB 3' untranslated region. Due to its high polymorphism information content (PIC) value (0.71 for haplotypes of BanII, HinfI, and KpnI RFLPs) and proximity to the centromere. FNRB will prove to be a highly useful marker for genetic linkage studies of multiple endocrine neoplasia type 2A (MEN2A) as well as for chromosome-10 linkage studies in general.
Chromosome Mapping↗
Assignment of the gene encoding the beta-subunit of the human fibronectin receptor (beta-FNR) to chromosome 10p11.2.
A cDNA corresponding to the beta-subunit of the human fibronectin receptor (beta-FNR) was used as a probe in Southern blot analysis of mouse/human somatic cell hybrid DNAs and in in situ hybridization to metaphase chromosomes. The beta-FNR cDNA detects sequences present on human chromosome 10 as well as recognizing homologous sequences in the genome of the mouse parent of the somatic cell hybrids. In situ hybridization refined the localization of human sequences reacting with the beta-FNR cDNA to 10p11.2. The A-1A5 monoclonal antibody which recognizes the beta-subunit of the fibronectin receptor on the cell surface was used to confirm that the sequences present on chromosome 10 correspond to those required for expression of beta-FNR.
Animals↗
Y chromosome specific probes identify breakpoint in a 45,X/46,X,del(Y)(pter----q11.1:) karyotype of an infertile male.
An infertile male patient with a 45,X peripheral blood karyotype and a 45,X/46,X,del(Y)(pter----q11.1:) mosaic skin fibroblast karyotype is described. Steroid sulphatase (STS) activity was normal. Recombinant DNA studies using Y chromosome specific probes suggest that almost the entire long arm of the Y chromosome is deleted.
Chromosome Deletion↗
MIC2: a human pseudoautosomal gene.
MIC2 and XGR are the only known pseudoautosomal genes in man. MIC2 encodes the 12E7 antigen, a human cell-surface molecule of unknown function. XGR regulates, in cis, the expression of the XG and MIC2 genes. DNA probes derived from the MIC2 locus have been used in the construction of a meiotic map of the pseudoautosomal region and a long range restriction map into the X- and Y-specific chromosome domains. MIC2 is the most proximal marker in the pseudoautosomal region and recombination between the sex chromsomes only rarely includes the MIC2 locus. Our long-range restriction maps and chromosome walking experiments have localized the pseudoautosomal boundary within 40 kilobases adjacent to the 3' end of the MIC2 gene. The same maps have been used to predict the chromosomal location of TDF.
Amino Acid Sequence↗
Analysis of methylation of a human X located gene which escapes X inactivation.
The gene MIC2 is located in the pseudoautosomal region at the ends of the short arms of the X and Y chromosomes. In females MIC2 escapes X inactivation. We have analyzed the methylation pattern of MIC2 on the active X, the inactive X chromosomes, and the Y chromosome. The 5' end of the gene contains a GC rich region which is unmethylated on the active X, the inactive X and on the Y. The body of the gene is characterized by variable methylation.
Base Sequence↗
Evolutionary conservation of the human homologue of the yeast cell cycle control gene cdc2 and assignment of Cd2 to chromosome 10.
The human homologue of the fission yeast Schizosaccharomyces pombe cell cycle control gene cdc2 has been assigned to chromosome 10. DNA hybridization reveals that this gene is highly conserved in vertebrates. The human CDC2 gene probe detects a simple two-allele polymorphism in Taq1-digested DNA.
Alleles↗
Absence of methylation of a CpG-rich region at the 5' end of the MIC2 gene on the active X, the inactive X, and the Y chromosome.
We have identified and characterized a Hpa II tiny fragment (HTF) island associated with the promoter region of the pseudoautosomal gene MIC2. The MIC2 HTF island is unmethylated on both the active and inactive X chromosome and is similarly unmethylated on the Y chromosome. Unlike the majority of genes borne on the X chromosome, MIC2 fails to undergo X chromosome inactivation. HTF islands associated with X chromosome-linked genes that are inactivated are highly methylated on the inactive or transcriptionally silent homologue. The failure of MIC2 to undergo X chromosome inactivation correlates with the lack of methylation of the HTF island at the 5' end of the gene. These results provide further evidence that DNA methylation plays an important role in the phenomenon of X chromosome inactivation.
Antigens, Surface↗
A BamHI RFLP recognised by an anonymous chromosome 20 probe, p4.8 (D20S14).
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Chromosomes, Human, Pair 20↗
Isolation of a sequence which maps close to the human sex determining gene.
A sequence mapping close to the human sex determining gene (TDF) has been isolated from a lambda library constructed with DNA derived from a chromosome transfectant hybrid cell line. This sequence is shown to be present in the DNA of X-Y interchange males at a very high frequency and, based on these studies, it is categorised with the sequence defined by the probe, GMGY3, as the closest known Y chromosome derived marker to TDF. In contrast to GMGY3, however, this locus shares no homology with any other human chromosome. Southern blot analysis also reveals specific hybridization to the Y chromosome of other primates. It therefore defines, for the first time, a conserved and Y chromosome unique locus that is near to TDF.
Base Sequence↗
A polymorphic locus, D10S5, at 10q21.1.
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Chromosomes, Human, Pair 10↗
Linkage analysis of multiple endocrine neoplasia type 2A (MEN-2A) and three DNA markers on chromosome 20: evidence against synteny.
Members of four families in which multiple endocrine neoplasia type 2A (MEN-2A) is segregating were genotyped for three chromosome #20 DNA markers. Close linkage is excluded for the genetic locus of MEN-2A (MEN2A) with each marker locus tested. Using multipoint analysis, the MEN2A locus was excluded from a region 32.5 cM in length encompassing D20S5 and D20S6, two loci that previously had been mapped to the chromosome 20p12.2 region containing the putative deletion associated with MEN-2. In total, we excluded approximately 90.5 cM of chromosome #20 as a possible location of the MEN2A locus. The data from this study do not support increased recombination on the short arms of chromosome #20 and were insufficient to support heterogeneity of MEN-2A as possible explanations for failure to detect linkage between MEN2A and D20S5 or D20S6.
Chromosome Banding↗
Recombination between the X and Y chromosomes: implications for the relationship between MIC2, XG and YG.
Three loci affect the levels of expression of the 12E7 antigen on red blood cells: MIC2, the pseudoautosomal structural gene for the 12E7 antigen; XG, an X-linked red cell blood group locus and YG, a polymorphic Y-linked locus. In this report we describe recombination between XG and MIC2 and an exchange between the X and Y chromosomes which included YG. These results have prompted us to propose a new model describing the genetic relationship between the XGa and 12E7 antigens.
Antibodies, Monoclonal↗