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PubMed1997

AMP-activated protein kinase isoenzyme family: subunit structure and chromosomal location.

The AMP-activated protein kinase (AMPK) consists of catalytic alpha and non-catalytic, beta and gamma (38 kDa) subunits and is responsible for acting as a metabolic sensor for AMP levels. There are multiple genes for each subunit and we find that rat liver AMPK-alpha2 isoform catalytic subunit is associated with beta1 and gamma1 and not with beta2 or gamma2 subunit isoforms. The beta1 and gamma1 isoforms are also subunits of the alpha1 isoform. The sequence of cloned human AMPK-beta1 is 95% identical in amino acid sequence with rat beta1. Human chromosomal localizations were determined for AMPK-alpha1 (5p11-p14), AMPK-beta1 (12q24.1-24.3) and AMPK-gamma1 (12q12-q14), respectively.

AMP-Activated Protein Kinases↗
PubMed1998

Genomic structure and chromosomal location of the human TGFbeta-receptor interacting protein-1 (TRIP-1) gene to 1p34.1.

The human TRIP-1 (transforming growth factor-beta (TGBbeta)-receptor interacting protein-1) cDNA encodes a protein able to associate specifically with the type II TGFbeta receptor. It is phosphorylated on serine and threonine by this receptor kinase which makes it a strong candidate as part of the TGFbeta signal transduction pathway. We have isolated the genomic sequence of TRIP-1 and found that the complete coding region is organised into 11 exons ranging from 39 to 397 bp and spanning approximately 9 kb of genomic DNA. The 5' flanking region lacks a TATA box but is GC-rich, suggesting that it is a constitutively expressed gene which is in agreement with its wide pattern of expression. Fluorescence in situ hybridisation mapped the TRIP-1 gene to chromosome 1p34.1 whereas a pseudogene is located on chromosome 7q32.

Chromosomes, Human, Pair 1↗
PubMed1999

Determination of cDNA, gene structure and chromosomal localization of the novel human 17beta-hydroxysteroid dehydrogenase type 7(1).

We have identified human 17beta-hydroxysteroid dehydrogenase type 7 (17beta-HSD 7). The novel human cDNA encodes a 37 kDa protein that shows 78 and 74% amino acid identity with rat and mouse 17beta-HSD 7, respectively. These enzymes are responsible for estradiol production in the corpus luteum during pregnancy, but are also present in placenta and several steroid target tissues (breast, testis and prostate) as revealed by RT-PCR. The human 17beta-HSD 7 gene (HSD17B7) consists of nine exons and eight introns, spanning 21. 8 kb and maps to chromosome 10p11.2 close to susceptibility loci for tumor progression, obesity and diabetes. The HSD17B7 promoter (1.2 kb) reveals binding sites for brain-specific and lymphoid transcription factors corresponding to additional expression domains in hematopoietic tissues and the developing brain as identified by in silico Northern blot.

17-Hydroxysteroid Dehydrogenases↗
PubMed1998

Chromatin structure and chromosome aberrations: modeling of damage induced by isotropic and localized irradiation.

Various models for the nuclear architecture in interphase cell nuclei have been presented, proposing a territorial or a non-territorial organization of chromosomes. To better understand the correlation between nuclear architecture and the formation of chromosomal aberrations, we applied computer simulations to model the extent of radiation induced chromosome damage under certain geometrical constraints. For this purpose, chromosomes were described by different models, which approximate the chromatin fiber by a polymer chain, folded in different ways. Corresponding to the different condensation levels, a territorial or a non-territorial organization of chromosomes was obtained. To determine the relative frequencies of radiation induced damage, the effects of isotropic ionizing radiation and of a focused laser UV-beam were studied. For isotropic ionizing radiation, the calculated translocation frequencies showed no differences between territorial and non-territorial models except for one special case. For localized irradiation, the results of both organizations were clearly different, with respect to the total number of damaged chromosomes per cell. The predictions agreed well with the experimental data available.

Animals↗
PubMed1999

Estrogen, DNA damage and mutations.

Estrogen administration to rodents results in various types of DNA damage and ultimately leads to tumors in estrogen-responsive tissues. Yet these hormones have been classified as nonmutagenic, because they did not induce mutations in classical bacterial and mammalian mutation assays. In this review, we have discussed the induction by estrogens of DNA and chromosomal damage and of gene mutations, because the classical assays were designed to uncover mutations only at one specific locus and could not have detected other types of mutations or changes in other genes. Various types of estrogen-induced DNA damage include: (a) direct covalent binding of estrogen quinone metabolites to DNA; (b) enhancement of endogenous DNA adducts by chronic estrogen exposure of rodents; (c) free radical generation by metabolic redox cycling between quinone and hydroquinone forms of estrogens and free radical damage to DNA such as strand breakage, 8-hydroxylation of purine bases of DNA and lipid hydroperoxide-mediated DNA modification. Two different types of chromosomal damage have also been induced by estrogen in vivo and in cells in culture such as numerical chromosomal changes and also structural chromosomal aberrations. Gene mutations have been induced in several cell types in culture either by the parent estrogen or by reactive estrogen quinone metabolites. Furthermore, in estrogen-induced kidney tumors in hamsters, several mutations have been observed in the DNA polymerase beta gene mRNA. Estradiol also induces microsatellite instability in these kidney tumors and in premalignant kidney exposed to estradiol. Although this work is still ongoing, it can be concluded that estrogens are complete carcinogens capable of tumor initiation by mutation potentially in critical genes. The hormonal effects of estrogens may complete the development of tumors.

Animals↗
PubMed1998

MIX-1: an essential component of the C. elegans mitotic machinery executes X chromosome dosage compensation.

We show that a functional component of the C. elegans mitotic machinery regulates X chromosome gene expression. This protein, MIX-1, is a member of the dosage compensation complex that associates specifically with hermaphrodite X chromosomes to reduce their gene expression during interphase. MIX-1 also associates with all mitotic chromosomes to ensure their proper segregation. Both dosage compensation and mitosis are severely disrupted by mix-1 mutations. MIX-1 belongs to the SMC protein family required for mitotic chromosome condensation and segregation in yeast and frogs. Thus, an essential, conserved component of mitotic chromosomes has been recruited to the dosage compensation process. Rather than dosage compensation and mitosis being achieved by two separate sets of related genes, these two processes share an identical component, indicating a common mechanism for establishing higher order chromosome structure and proper X chromosome gene expression.

Amino Acid Sequence↗
PubMed1999

Cloning, tissue-specific expression, gene structure and chromosomal localization of human phosphatidylcholine transfer protein.

Phosphatidylcholine transfer protein (PC-TP) is a cytosolic protein that catalyzes intermembrane transfer of phosphatidylcholines in vitro. We have cloned a cDNA encoding the human ortholog of PC-TP and have determined its tissue-specific expression as well as genomic organization. Radiation hybrid mapping localized the human gene, PCTP, to chromosome 17q21-22 and PCR-based single strand conformation polymorphism analysis of an interspecific backcross assigned mouse Pctp to the region of syntenic conservation on chromosome 11.

Amino Acid Sequence↗
PubMed1999

cDNA cloning, genomic structure and chromosomal localization of the human BUP-1 gene encoding beta-ureidopropionase.

A full-length cDNA clone encoding human beta-ureidopropionase was isolated. A 1152-nucleotide open reading frame which corresponds to a protein of 384 amino acids with a calculated molecular weight of 43¿ omitted¿158 Da, surrounded by a 5'-untranslated region of 61 nucleotides and a 3'-untranslated region of 277 nucleotides was identified. The protein showed 91% similarity with the translation product of the rat beta-ureidopropionase cDNA. Expression of the human cDNA in an Escherichia coli and eukaryotic COS-7 expression system revealed a very high beta-ureidopropionase enzymatic activity, thus confirming the identity of the cDNA. Since human EST libraries from brain, liver, kidney and heart contained partial beta-ureidopropionase cDNAs, the enzyme seems to be expressed in these tissues, in agreement with the expression profile of this enzyme in rat. Using the human cDNA as a probe a genomic P1 clone could be isolated containing the complete human beta-ureidopropionase gene. The gene consist of 11 exons spanning approximately 20 kB of genomic DNA. Fluorescence in situ hydridization localized the human beta-ureidopropionase gene to 22q11.2.

Amidohydrolases↗
PubMed2000

Gene structure and chromosome mapping of mouse transcription elongation factor S-II (Tcea1).

We report the organization and chromosome localization of the mouse transcription elongation factor S-II gene (Tcea1). This gene was found to be a single copy gene consisting of 10 exons spanning approximately 30kb. Its organization was the same as those of the mouse testis-specific S-II gene (Tcea2) and Xenopus general S-II gene (xTFIIS.oA), but different from that of the human S-II gene family. We also identified a processed pseudogene (Tcea1-ps1) with a sequence highly homologous to those of S-II cDNAs but containing a translation termination codon within its open reading frame. Linkage analysis showed that Tcea1 and Tcea1-ps1 are mapped on mouse chromosomes 1 and 15, respectively. Relationships between Tcea1 and S-II cDNAs isolated so far are discussed.

Animals↗
PubMed2000

Genomic structure and chromosomal mapping of the mouse hic-5 gene that encodes a focal adhesion protein.

The hic-5 gene encodes a focal adhesion protein that has striking similarity to paxillin. Genomic clones of the mouse hic-5 gene were isolated, and included 10 exons that covered the whole mouse mRNA sequence. Comparison of the sequence with those in the expressed sequence tag database suggested that the hic-5 gene contained an extra exon (named exon 1') located about 1kb upstream of exon 1, and mouse cells seemed to express two alternatively spliced forms of mRNA. All the exon-intron boundaries followed the GT/AG rule. Physical mapping and fluorescent in situ hybridization analysis indicated that the hic-5 gene is located on mouse chromosome 7, 60. 0cM from the centromere.

Amino Acid Sequence↗
PubMed2000

Cloning, genomic structure and chromosomal localization of the gene encoding mouse DNA helicase RecQ helicase protein-like 4.

Five members of the RecQ helicase family, RECQL, WRN, BLM, RECQL4 and RECQL5 have been identified in humans. WRN and BLM have been demonstrated to be the responsible genes in Werner and Bloom syndromes, respectively. RECQL4 (RecQ helicase protein-like 4) was identified as a fourth member of the human RecQ helicase family bearing the helicase domain, and it was subsequently shown to be the responsible gene in Rothmund-Thomson syndrome. Here, we isolated mouse RECQL4 and determined the DNA sequence of full-length cDNA as well as the genome organization and chromosome locus. The mouse RECQL4 consists of 3651 base pairs coding 1216 amino acid residues and shares 63.4% of identical and 85.8% of homologous amino acid sequences with human RECQL4. The RECQL4 gene was localized to mouse chromosome 15D3 distal-E1 and rat chromosome 7q34 proximal. They were mapped in the region where the conserved linkage homology has been identified between the two species. Twenty-two exons dispersed over 7 kilo base pairs and all of the acceptor and donor sites for splicing of each exon conformed to the GT/AG rule. Our observations regarding mouse RECQL4 gene will contribute to functional studies on the RECQL4 products.

Adenosine Triphosphatases↗
PubMed2001

Cloning, genomic structure and chromosomal localization of the gene encoding mouse DNA helicase RECQL5beta.

Five members of the RecQ helicase family, RECQL, WRN, BLM, RTS and RECQL5, have been found in human and three of them (WRN, BLM and RTS) were disclosed to be the genes responsible for Werner, Bloom and Rothmund-Thomson syndromes, respectively. RECQL5 (RecQ helicase protein-like 5) was isolated as the fifth member of the family in humans through a search of homologous expressed sequence tags. The gene is expressed with at least three alternative splicing products, alpha, beta and gamma. Here, we isolated mouse RECQL5 beta and determined the DNA sequence of full-length cDNA as well as the genome organization and chromosome locus. The mouse RECQL5 beta gene consists of 2949 bp coding 982 amino acid residues. Comparison of amino acid sequence among human (Homo sapiens), mouse (Mus musculus), Drosophila melanogaster and Caenorhabditis elegans RECQL5 beta homologs revealed three portions of highly conserved regions in addition to the helicase domain. Nineteen exons are dispersed over 40 kbp in the genome and all of the acceptor and donor sites for the splicing of each exon conform to the GT/AG rule. The gene is localized to the mouse chromosome 11E2, which has a syntenic relation to human 17q25.2-q25.3 where human RECQL5 beta exists. Our genetic characterizations of the mouse RECQL5 beta gene will contribute to functional studies on the RECQL5 beta products.

Amino Acid Sequence↗
PubMed1997

Structure and chromosomal mapping of the mouse P2X3 gene.

P2X3 is one of seven cloned ATP-gated non-selective cation channels. We have isolated a full-length mouse P2X3 gene from a phage lambda-129/Sv genomic library. The gene consists of 12 exons spanning a locus of approximately 40 kb. No significant similarities have been found between the genomic organisation of the mouse P2X3 gene and genes encoding other ion channels. The encoded mouse P2X3 protein consists of 397 amino acids and shows 99% identity with rat P2X3. Using RNase protection and primer extension assays, multiple transcription initiation sites have been mapped in the mouse P2X3 promoter to a region 162-168 bp upstream of the translation initiation codon. The P2X3 gene has been mapped to mouse chromosome 2p by fluorescence in situ hybridisation. The RAG locus-associated gene T160 is located 1.8 kb upstream of the transcription start site of mouse P2X3 gene. The promoter region of the mouse P2X3 gene lacks a conventional TATA and CCAAT consensus sites, and initiator elements. P2X3 is the first member of the P2X gene family to be completely characterised.

Amino Acid Sequence↗
PubMed1997

The mouse Plk gene: structural characterization, chromosomal localization and identification of a processed Plk pseudogene.

The Plk gene encodes a serine/threonine protein kinase believed to be important for the normal progression of mammalian cells through the cell cycle. In this paper, we report the genomic organization of the mouse Plk gene. The mouse Plk gene encompasses 16 kb of the mouse genome and is organised into 10 exons. Based on homology with the human PLK1 promoter region, the putative mouse promoter region includes a CCAAT motif but lacks the conventional TATA motif. The proposed promoter region contains consensus binding sites for several transcriptional regulators, including Sp1 and AP2. In addition to the active copy of Plk, Plk exists as a processed pseudogene. Using RFLP analysis, we have localized the active Plk gene to mouse Chromosome 7 and the processed pseudogene to mouse Chromosome 5. Southern blot analysis of DNA from a limited number of other mammalian species suggests that the duplication is confined to the mouse. Parsimony analysis suggests that the gene duplication leading to the mouse Plk pseudogene occurred after the rat-mouse split.

Animals↗
PubMed1997

Polymeric immunoglobulin receptor gene of mouse: sequence, structure and chromosomal location.

We have isolated genomic clones of a mouse gene (pIgR) for polymeric immunoglobulin receptor which mediates transport of polymeric immunoglobulins. The four overlapping clones obtained retain a DNA fragment spanning approx. 32 kb altogether, and the base sequences of these clones were determined. Comparison with cDNA sequence identified 11 exons and 10 introns, as well as a polyadenylation site. We have also identified presumptive regulatory elements on the 5' presumptive untranscribed region and a polyadenylation signal on the 3' untranslated region. Thus, the DNA cloned covers the whole area which is transcribed into mRNA. Also, in situ hybridization locates this gene on the long arm of the first chromosome of mouse.

Animals↗
PubMed1998

Cloning of a retinally abundant regulator of G-protein signaling (RGS-r/RGS16): genomic structure and chromosomal localization of the human gene.

Regulators of G-protein signaling (RGS) constitute a family of GTPase-activating proteins with varying tissue-specific expression patterns and G-protein alpha subunit specificities. Here, we describe the molecular cloning of the human RGS-r/RGS16 cDNA, encoding a predicted polypeptide of 23kDa that shows 86% identity to mouse RGS-r. Northern blot analysis shows that, like the mouse Rgs-r message, hRGS-r mRNA is abundantly expressed in retina, with lower levels of expression in most other tissues examined. Characterization of the genomic organization of the hRGS-r gene shows that it consists of five exons and four introns. We have also mapped the human RGS-r /RGS16 gene to chromosome 1q25-1q31 by fluorescence in situ hybridzation. Analysis of human ESTs reveals that at least five members of the RGS gene family map to chromosome 1q, suggesting that at least part of the RGS family arose through gene duplication. The chromosomal location, retinal abundance, and presumed function of the human RGS-r protein in desensitizing photoreceptor signaling make the RGS-r/RGS16 locus a candidate for mutations responsible for retinitis pigmentosa with para-arteriolar preservation of retinal pigment epithelium (RP-PPRE or RP12), an autosomal recessive disorder previously mapped to 1q31.

Amino Acid Sequence↗
PubMed1998

Genomic structure and chromosomal mapping of the human and mouse hippocalcin genes.

In an attempt to elucidate the possible relationship of hippocalcin to neurological disorders, we isolated and analyzed the human and mouse hippocalcin genes. The human and mouse hippocalcin genes contain three exons and two introns, and span approximately 7 and 8kb, respectively. The exon/intron splice junctions of the human and mouse genes are all situated in exactly the same position and are not consistently placed with respect to the coding regions of the tandemly repeated EF-hand motifs. The amino acid sequences of human and mouse hippocalcins deduced from the genes are 100% identical. Within the 2-kb 3'-flanking sequences of the human and mouse genes, one conserved polyadenylation signal was identified at positions 762 and 823bp downstream from TAG, respectively. Within the 2.6-kb 5'-flanking sequences of the human and mouse genes, neither a canonical 'TATA' box nor a 'CAAT' box was found. Southern blot analysis of the human and mouse genomic DNAs demonstrated that the positive bands coincide exactly with those expected from the sequence of the cloned genes, indicating that the human and mouse hippocalcin genes are present as a single-copy gene. Fluorescence in-situ hybridization revealed that the human hippocalcin gene is located at chromosome 1 p34.2-35 and the mouse hippocalcin gene at chromosome 4 D2-D3.

Animals↗
PubMed1999

Structure and chromosome localization of the human CASP8 gene.

The human CASP8 gene, whose product is also known as caspase 8 and FLICE, encodes an interleukin-1beta converting enzyme (ICE)-related cysteine protease that is activated by the engagement of several different death receptors. Caspase 8 is immediately recruited to the Fas receptor once it oligomerizes, and its protease activity is crucial for the apoptotic response generated by the resulting death-inducing signaling complex (DISC). We report here that the CASP8 gene contains at least 11 exons spanning approximately 30kb on human chromosome band 2q33-34. This region of human chromosome 2 was previously reported as the location of the CASP10 gene, whose product is closely related to caspase 8. Chromosome 2 band q33-34 is also involved in tumorigenesis, with loss of heterogeneity (LOH) being reported in a number of tumors. We also report EcoRI and HindIII polymorphisms that may prove to be useful in disease analysis. Both caspases 8 and 10 contain long pro-domains with duplicated death effector domains (DEDs), as well as their corresponding cysteine protease catalytic domains. Thus, it appears that CASP8 and CASP10 have evolved by tandem gene duplication, much like the CASP1, CASP4 and CASP5 gene cluster on human chromosome 11q22.2-22.3.

Blotting, Northern↗