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F Pedeutour

Publications and source records attributed to F Pedeutour.

46 records · Page 3Linked to original sources

Localization of the gene for DNA polymerase epsilon (POLE) to human chromosome 12q24.3 and rat chromosome 12 by somatic cell hybrid panels and fluorescence in situ hybridization.

DNA polymerase epsilon [DNA pol epsilon (EC 2.7.7.7)] is one of the four nuclear DNA polymerases in eukaryotic cells. The mammalian enzyme is involved in DNA repair and possibly also in replication of chromosomal DNA. The gene encoding pol epsilon (POLE) was assigned to human and rat chromosomes 12 by Southern blot analysis of genomic DNA from mouse-human and mouse-rat somatic cell hybrid panels using human cDNA probe. The human gene was then regionally localized to band 12q24.3 by fluorescence in situ hybridization of metaphase spreads of chromosomes from human lymphocytes using genomic DNA probe. POLE is closely linked to HNF1A, a gene encoding a liver-enriched transcription factor, HNF1 alpha. The two genes thus define a new synteny group retained on human and rat chromosomes 12. Another gene mapping to the same or close-by region as human POLE is a gene for inherited disorder tuberous sclerosis 3, TSC3.

Animals↗

Assignment of the human pro-melanin-concentrating hormone gene (PMCH) to chromosome 12q23-q24 and two variant genes (PMCH1 and PMCHL2) to chromosome 5p14 and 5q12-q13.

Melanin-concentrating hormone (MCH) is a peptide that has been isolated from salmon pituitary and rat hypothalamus. In mammals, pro-MCH (PMCH) encodes two putative peptides, named NEI and NGE, in addition to MCH. Those peptides are expressed predominantly in hypothalamus and display a broad array of functions in rat brain. We have previously mapped the PMCH locus on human chromosome 12q and rat chromosome 7. Genomic cloning has revealed the existence of two distinct MCH genes in human: one authentic and one variant. In this report, we describe Southern blotting analysis with DNA from a panel of somatic cell hybrids and demonstrate that the authentic human MCH (hMCH) gene is located as expected on chromosome 12, while the variant form of hMCH gene is located on chromosome 5. Direct chromosomal assignment of the authentic and variant hMCH genes was obtained by using fluorescence in situ hybridization on metaphase chromosomes. A strong signal was observed in 12q23-q24 with the authentic hMCH genomic DNA probe. Surprisingly, two signals were conspicuously found in 5p14 and 5q12-q13 with different variant hMCH genomic DNA probes. These loci were designated PMCHL1 and PMCHL2. Evidence of physiological and pathological data in rodents together with locus linkage analyses in human suggests that hMCH authentic and variant genes may be involved in human brain disorders.

Animals↗

Comparative genomic hybridization as a tool to define two distinct chromosome 12-derived amplification units in well-differentiated liposarcomas.

Well-differentiated liposarcomas (WDLPS) are frequently characterized by a near-diploid karyotype with supernumerary ring and/or giant rod-shaped marker chromosomes. We have shown, using fluorescence in situ hybridization (FISH) and molecular strategies, that these markers contain chromosome 12-derived sequences. Here we report the analysis of six WDLPS for the presence of amplified DNA segments by means of the recently developed comparative genomic hybridization (CGH) strategy. Two distinct chromosome 12-derived amplification units could be identified in all tumors examined, one located in the q14-q15 region as expected, the second unexpectedly mapping to q21.3-q22. Our results indicate that the concerted amplification of these two distinct regions on the long arm of chromosome 12 may be a consistent characteristic of WDLPS. These amplifications are most likely directly related to the presence of supernumerary ring and/or giant marker chromosomes in this group of soft tissue tumors.

Cell Differentiation↗

Complex composition and co-amplification of SAS and MDM2 in ring and giant rod marker chromosomes in well-differentiated liposarcoma.

Extra abnormal chromosomes (rings and giant rods) containing chromosome 12 sequences are characteristic of well-differentiated liposarcoma (WDLPS). By whole chromosome painting we found in 6 WDLPS that minimally 5 chromosomes had contributed to the formation of the extra abnormal chromosomes. To the constant chromosome 12 contribution, sequences were variably added from chromosomes 1, 4, and 16. Material from chromosomes 1, 4, and 12 was identified by painting in interphase nuclear projections ("blebs") and in micronuclei consistent with the concept that blebs are precursors to micronuclei. The complexity of the mechanisms generating the extra abnormal chromosomes in WDLPS was also attested to by the diversity and, in some cases, intricacy of the patterns of fluorescence. To begin to fathom the function of the extra abnormal chromosomes we examined the amplification of genes, including SAS, MDM2, and GADD153/CHOP, known to be in the region 12q13-14. SAS and MDM2 demonstrated constant co-amplification. GADD153/CHOP, which is critically rearranged in myxoid liposarcoma, was not amplified in WDLPS.

Aged↗

Mapping of the 12q12-q22 region with respect to tumor translocation breakpoints.

The consistent involvement of the region 12q13-q15 in numerous human tumors speaks in favor of the presence of genes that may contribute to oncogenesis. Mapping genes within this region of chromosome 12 is a necessary step toward the identification of those that play a role in this process. We have undertaken a multiplex analysis using translocation breakpoint mapping to order from the centromere to the telomere a series of 24 loci from the region 12q12-q22. Thirteen adipose tissue tumors with seven different chromosome changes involving the long arm of chromosome 12 (12q) were used. Since most of these loci are genes or anonymous DNA segments largely available to the scientific community, this map should be useful for investigation of genetic disorders associated with chromosome 12q. While these breakpoints were used as natural landmarks to order groups of loci, this work has positioned them more accurately, leading to a better chromosomal definition of the translocations than the one derived from standard cytogenetic studies.

Chromosome Mapping↗

Molecular cloning of a putative novel human bZIP transcription factor on chromosome 17q22.

We have cloned and characterized cDNA clones representing several mRNA isoforms generated by alternative splicing of a single gene localized to chromosome 17q22. Sequence analysis showed that the predicted translational product of the longest open reading frame (2316 nucleotides, 772 amino acids) is related to transcription factors of the basic leucine zipper (bZIP) class. The sequence contained several regions characteristic of transcriptional regulatory domains. A cluster of amino acids flanking the bZIP region on both sides was highly conserved between TCF11 and p45 NF-E2, a subunit of the human globin locus control region-binding protein, NF-E2. These same regions showed remarkable homology to two invertebrate proteins, CNC and skin-1, postulated to regulate embryonic development in Drosophila melanogaster and Caenorhabditis elegans, respectively.

Amino Acid Sequence↗

Supernumerary ring chromosomes containing chromosome 17 sequences. A specific feature of dermatofibrosarcoma protuberans?

Mystery surrounds the mechanisms by which the uncommon cutaneous tumor dermatofibrosarcoma protuberans (DP) arises and progresses. A clue may be at hand in the form of extra abnormal chromosomes (one of three ring chromosomes per case with or without other chromosome abnormalities) seen in some 10 cases, including five cases in our experience. The specificity of the rings to DP would be enhanced if the rings were found to contain a contribution from a constant chromosome. We here report fluorescence in situ hybridization (FISH) results bearing on the chromosomal content of DP rings, together with clinical, pathologic, and cytogenetic documentation of our first two cases, which were briefly reported earlier, and three new DP cases. To dissect a translocation (in our 2nd case), we probed by FISH and discovered chromosome 17 sequences in the rings in all five DP cases. Nonfluorescent bands were seen on some rings painted with a whole chromosome 17 probe, indicating the presence in these rings of foreign chromosome sequences. The complexity of the rings was underscored by the detection in only one case of chromosome 17 centromeric sequences. The situation in DP seems to have parallels to that in well-differentiated liposarcoma, another tumor of intermediate malignancy with extra abnormal marker chromosome containing contributions from a constant chromosome and variable donors. In DP the supernumerary rings are clearly specific and significant.

Adult↗

Fusion and amplification of two originally non-syntenic chromosomal regions in a mammary carcinoma cell line.

The FLG/FGFRI gene, encoding a receptor for members of the FGF family, is located at 8p11.2-p12. It is amplified, overexpressed, and not grossly rearranged in the MDA-MB-134 breast carcinoma cell line, whereas other genes from the pericentromeric 8p region are not amplified. The FGF4/HSTFI gene, located at 11q13, is also amplified with a substantial portion of the 11q13 region, but is not overexpressed in MDA-MB-134 cells. In this cell line, amplified sequences constitute a large homogeneously staining region (HSR) which is part of a marker chromosome containing chromosome 8 and chromosome 11 sequences. Using probes for the FGF4/HSTFI and the FLG/FGFRI genes in fluorescence chromosomal in situ hybridization, we show that the HSR contains de novo fused and amplified 11q13 and 8p11-p12 sequences associated in a complex structure containing approximately the same number of FGF4 and FGFRI genes. The significance of this genetic abnormality for MDA-MB-134 cells, and for breast carcinogenesis in general, is unknown, but may underlie a particular type of oncogene activation.

Breast Neoplasms↗