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Query: UNIPROT:P06889 (Mol)
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Samples of human adult lymphocytes, fetal lymphocytes, amniotic fluid cells, and chorionic villus cells were sexed independently by cytogenetics and DNA-DNA in situ hybridisation to a tritiated Y probe. For the in situ hybridisation analysis, the presence of Y bodies (hybridisation bodies) in 100 interphase nuclei were scored after autoradiography. In all, 82/83 samples were sexed in this way (one technical failure) and 78/82 were sexed by both in situ hybridisation and cytogenetics. There was complete agreement between the two methods. There was a considerable variation (40-100%) in the percentage of interphase nuclei with a hybridisation body among the male samples, but very few nuclei from female samples showed significant hybridisation. In situ hybridisation could be used to sex the conceptus when males but not females are at risk for various X-linked genetic disorders and may also be useful for detecting 45,X/46,XY mosaicism or polyploid/diploid mosaicism. This would be particularly useful for direct preparations of chorionic villus samples, which often prove difficult to analyse cytogenetically but offer the best means of avoiding maternal contamination. Some interphase nuclei had more than one hybridisation body, and this was most commonly found among amniotic fluid cells. Comparison of sizes of nuclei with one or two hybridisation bodies strongly suggested that most of the amniotic fluid cell nuclei with two hybridisation bodies were tetraploid.
Mol Reprod Dev 1989
PMID:Sexing the human fetus and identification of polyploid nuclei by DNA-DNA in situ hybridisation in interphase nuclei. 262 51

Part of the higher-order structure of chromatin is achieved by constraining DNA in loops ranging in size from 30 to 100 kilobase pairs; these loops have been implicated in defining functional domains and replicons and possibly in facilitating transcription. Because the human active and inactive X chromosomes differ in transcriptional activity and replication, we looked for differences in their chromatin loop structures. Since the islands of CpG-rich DNA at the 5' ends of X-linked housekeeping genes are the regions where functional differences in DNA methylation and nuclease sensitivity are found, we looked for scaffold association of these sequences after extraction of histones with lithium diiodosalicylate. Specifically, we examined the 5' CpG islands within the hypoxanthine phosphoribosyltransferase, glucose 6-phosphate dehydrogenase, P3, GdX, phosphoglycerate kinase type 1, and alpha-galactosidase loci in human lymphoblasts obtained from individuals with 1 to 4 X chromosomes. Although we detected no scaffold-associated regions near these genes, we found several such regions at the ornithine transcarbamylase and blood clotting factor IX loci. Our results suggest that the CpG islands are excluded from the nuclear scaffold and that even though transcriptionally active, housekeeping genes are less likely than X-linked tissue-specific genes to be scaffold associated. In all cases, the pattern of scaffold association was the same for loci on active and inactive X chromosomes.
Mol Cell Biol 1989 Jun
PMID:Chromatin loop structure of the human X chromosome: relevance to X inactivation and CpG clusters. 276 35

We investigated the conformation of the X-linked mouse hypoxanthine-guanine phosphoribosyltransferase gene (HPRT) promoter region both in chromatin from the active and inactive X chromosomes with DNase I and in naked supercoiled DNA with S1 nuclease. A direct comparison of the chromatin structures of the active and inactive mouse HPRT promoter regions was performed by simultaneous DNase I treatment of the active and inactive X chromosomes in the nucleus of interspecies hybrid cells from Mus musculus and Mus caroli. Using a restriction fragment length polymorphism to distinguish between the active and inactive HPRT promoters, we found a small but very distinct difference in the DNase I sensitivity of active versus inactive chromatin. We also observed a single DNase I-hypersensitive site in the immediate area of the promoter which was present only on the active X chromosome. Analysis of the promoter region by S1 nuclease digestion of supercoiled plasmid DNA showed an S1-sensitive site which maps adjacent to or within the DNase I-hypersensitive site found in chromatin but upstream of the region minimally required for normal HPRT gene expression.
Mol Cell Biol 1987 Aug
PMID:Nuclease sensitivity of the mouse HPRT gene promoter region: differential sensitivity on the active and inactive X chromosomes. 282 12

Ornithine carbamoyl transferase (Oct) is an X-linked gene which exhibits tissue-specific expression. To determine whether methylation of specific CpG sequences plays a role in dosage compensation or tissue-specific expression of the gene, 13 potentially methylatable sites were identified over a 30-kilobase (kb) region spanning from approximately 15 kb upstream to beyond exon II. Fragments of the Mus hortulanus Oct gene were used as probes to establish the degree of methylation at each site. By considering the methylation status in liver (expressing tissue) versus kidney (nonexpressing tissue) from male and female mice, the active and inactive genes could be investigated on active and inactive X-chromosome backgrounds. One MspI site, 12 kb 5' of the Oct-coding region, was cleaved by HpaII in liver DNA from males but not in kidney DNA from males and thus exhibited complete correlation with tissue-specific expression of the gene. Six other sites showed partial methylation, reflecting incomplete correlation with tissue-specific expression.
Mol Cell Biol 1987 Nov
PMID:Differential methylation of the ornithine carbamoyl transferase gene on active and inactive mouse X chromosomes. 282 19

The mammalian genome contains two genes encoding phosphoglycerate kinase; the pgk-1 gene is X-linked and is expressed in all cells except sperm, while the pgk-2 gene is expressed exclusively in sperm cells. The mouse genome contains no pseudogenes derived from pgk-2. On the other hand, the genomes of Balb/c and C3H/He strain mice contain six other regions with sequences homologous to those of pgk-1 cDNA. These pgk-related sequences are likely derived from the pgk-1 gene by retroposition because all are located on autosomal chromosomes and because none appear to be interrupted by introns. Two of the presumed pseudogenes contain sequences homologous to all regions of the pgk-1 cDNA while the other four genomic regions were truncated at the 5', 3', or both ends. One of the truncated pseudogenes was sequenced. Its pgk-related sequence was not flanked by direct repeats, suggesting that loss of the 5' and/or 3' ends of this retrogene may have occurred following its integration into the genome. Our evidence suggests that pgk-1-derived retroposons arose initially more than 100 million years ago and have continued to arise until so recently that some are unique to different mouse strains.
Somat Cell Mol Genet 1988 Jan
PMID:The family of mouse phosphoglycerate kinase genes and pseudogenes. 282 66

Females heterozygous for the two alleles dnc2 and dncM14 of the X-linked gene dunce (dnc), and carrying a copy of dnc+ on the second chromosome, have produced a cluster of six dnc+ progeny X-chromosomes from recombination experiments. Restriction site polymorphisms have been used as genetic markers to follow the parentage of dnc locus segments in these chromosomes. All six chromosomes are identical with respect to the spectrum of restriction site markers they carry in the dnc+ chromosomal region. In the progeny chromosomes, this region is comprised of sequences like the dncM14 X-chromosome and the translocation copy of dnc+. Sequences flanking the dnc gene in the progeny chromosomes are like the dncM14 chromosome. Internal to the gene but near the 5' end, is a segment from the dnc+ translocation which has apparently originated from an interchromosomal and premeiotic gene conversion event. In addition, two transposable elements have inserted into the progeny chromosomes, one towards the 5' end of dnc and the other near the 3' end. The insertion of these elements occurred premeiotically since all six chromosomes are structurally identical. The data are interpreted with respect to a potential role of transposable element transposition in the process of gene conversion.
Mol Gen Genet 1987 Jun
PMID:An interchromosomal gene conversion of the Drosophila dunce locus identified with restriction site polymorphisms: a potential involvement of transposable elements in gene conversion. 288 93

The molecular nature of formaldehyde (HCHO)-induced mutations was studied in both human lymphoblasts and E. coli. Thirty HPRT- human lymphoblast colonies induced by eight repetitive 150 microM HCHO treatments were characterized by Southern blot analysis. Fourteen of these mutants (47%) had visible deletions of some or all of the X-linked HPRT bands, indicating that HCHO can induce large losses of DNA in human lymphoblasts. In E. coli, DNA alterations induced by HCHO were characterized with use of the xanthine guanine phosphoribosyl transferase (gpt) gene as the genetic target. Exposure of E. coli to 4 mM HCHO for 1 hr induced large insertions (41%), large deletions (18%), and point mutations (41%). Dideoxy DNA sequencing revealed that most of the point mutations were transversions at GC base pairs. In contrast, exposure of E. coli to 40 mM HCHO for 1 hr produced 92% point mutations, 62% of which were transitions at a single AT base pair in the gene. Therefore, HCHO is capable of producing different genetic alterations in E. coli at different concentrations, suggesting fundamental differences in the mutagenic mechanisms operating at the two concentrations used. Naked pSV2gpt plasmid DNA was exposed to 3.3 or 10 mM HCHO and transformed into E. coli. Most of the resulting mutations were frameshifts, again suggesting a different mutagenic mechanism.
Environ Mol Mutagen 1988
PMID:Molecular analysis of formaldehyde-induced mutations in human lymphoblasts and E. coli. 290 Jul 62

Chromosome-mediated gene transfer (CMGT) lines were shown to be convenient donors of genomic sequences from specific regions of the genome adjacent to selectable markers. Two libraries were prepared from CMGT lines carrying sequences spanning the long arm of the human X chromosome from HPRT (Xq26) to G6PD (Xq28). A series of 22 CMGT lines sharing the same selectable marker (HPRT) were used in conjunction with five standard translocation hybrids to provide fine-resolution regional mapping of the nonrepetitive X specific probes isolated from the libraries. The order of three human recombinant sequences with respect to known X-linked markers is: PGK (Xq13), 05-02 (DXS78); HPRT (Xq26), 07-03 (DXS79); surface antigen S11 (Xq27), 07-14 (DXS80); and G6PD (Xq28).
Somat Cell Mol Genet 1985 Sep
PMID:Isolation and regional mapping of random X sequences from distal human X chromosome. 299 37

The X-linked sgs4 gene of Drosophila melanogaster encodes a salivary glue protein. Non-dosage-compensated alleles of this gene have been described by G. Korge, in which males accumulate only about half of the Sgs4 polypeptide as do females. We show that the Sgs4 mRNA levels in dosage-compensated and non-dosage-compensated strains parallel the levels of Sgs4 polypeptide. Korge's genetic analysis of one of the non-dosage compensated alleles suggests that dosage compensation is controlled by sequences that lie 5' to the coding region. Sequences important for regulating the absolute levels of transcription of sgs4 have been identified as residing within a region of 600 base-pairs 5' to the site of transcription initiation. We have sequenced this region from two non-dosage-compensated strains and find no significant deviation from the sequence of dosage-compensated alleles. We therefore conclude that sequences that act to mediate the dosage compensation of sgs4 must lie outside this 600 base-pair region.
J Mol Biol 1986 Feb 20
PMID:Dosage compensation at the sgs4 locus of Drosophila melanogaster. 301 92

In order to map human PGK sequences, DNA was prepared from 55 human-mouse somatic cell lines. The DNA was digested to completion with HindIII and Southern filters prepared. These filters were hybridized at high stringency conditions to a human PGK cDNA. Mouse and human X-linked and autosomal bands were distinguished and, in addition to known X-linked sequences, two autosomal PGK sequences were mapped: a 1-kb band to chromosome 19 and a 5-kb band to chromosome 6. The PGK cDNA probe was also hybridized to flow-sorted chromosomes confirming the presence of PGK sequences on the X chromosome and chromosomes 6 and 19.
Somat Cell Mol Genet 1986 Jul
PMID:Mapping of human autosomal phosphoglycerate kinase sequence to chromosome 19. 301 19


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