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Genomic structure and chromosomal mapping of the mouse STOP gene (Mtap6).

The microtubule associated protein STOP (Stable Tubule Only Polypeptide) is a calmodulin-regulated protein able to induce a high degree of microtubule stability. STOP is abundant in neurons which contain large subpopulations of stable microtubules. Genomic clones spanning 67 kb and encompassing the mouse STOP gene (Mtap6) have been isolated and characterized. These clones derive from a single gene mapping to the E2-F1 region of mouse chromosome 7. The gene is composed of 4 exons that exhibit conventional vertebrate splicing sequences. Transcription of the gene initiate at multiple sites in a 85 nucleotide region located 530 bases upstream the translation initiation codon. Accordingly, the 5' flanking region of the gene lacks a TATA box or an initiator element at usual position. The protein encoded by the mouse STOP gene (Mtap6) is composed of 906 amino acids and presents a 91% identities with the rat brain STOP.

Amino Acid Sequence↗

Genomic structure and chromosomal localization of the human interleukin 15 gene (IL-15).

Interleukin 15 (IL-15) is a novel cytokine whose biological activities are similar to those of interleukin 2 (IL-2). The genomic sequence of human IL-15 has been isolated based on its sequence homology with a cDNA clone encoding human IL-15. The human sequence is 14968 bp in length and includes all six protein-coding exons and five introns. The location of the introns in the human sequence is identical to their positions in the murine IL-15 gene. The same is true for the overall size of the gene, which was estimated to be at least 32 kb. Using Polymerase Chain Reaction (PCR) with gene-specific primers on a panel of human/rodent hybrid cell DNAs, as well as by fluorescence in situ hybridization the human IL-15 gene was mapped to chromosome 4 region q25-35.

Amino Acid Sequence↗

HSP70 is involved in the control of chromosomal transcription in the amphibian oocyte.

The amphibian oocyte represents an excellent model for the study of transcription regulation. Indeed, any modification of transcriptional activity is directly reflected in lampbrush chromosome structure by concomitant morphological changes. Previous studies have led to the hypothesis of a putative role for heat-shock proteins HSP70 and/or HSC70 in transcriptional processes in the oocyte. In order to dissect out the relative role of HSP70 or HSC70 in these processes, we used an oligo-antisense strategy to specifically inhibit the function of the targeted protein. Effects of hsc70 and hsp70 antisense oligodeoxynucleotides were analyzed in terms of both mRNA quantity and protein synthesis. Their effects on oocyte transcription were analyzed at the level of structural organization of lampbrush chromosomes and nucleolar transcriptional activity. Our results show that specific inactivation of hsc70 mRNA by hsc70 antisense oligos led to a reversible inhibition of lampbrush chromosome transcription. However, such reversible inhibition of transcription is considered non-sequence specific since it is also induced by any oligo. In contrast, specific inactivation of hsp70 mRNA by hsp70 antisense oligos, which is correlated with a drop of HSP70 neosynthesis, results in an irreversible inhibition of lampbrush chromosome transcription. Furthermore, our results show that the inactivation of hsp70 or hsc70 mRNAs does not affect nucleolar transcription. Such data suggest a role for HSP70 in the control of chromatin modifications related to RNA polymerase II transcriptional activity.

Animals↗

The human C/EBP delta (CRP3/CELF) gene: structure and chromosomal localization.

In an attempt to identify C/EBP-like transcription factors expressed in the prostate, a cDNA homologous to the mouse C/EBP delta (CRP3) and the rat CELF gene was isolated. A genomic clone containing the entire C/EBP delta gene was isolated using a cDNA fragment as a probe. The gene was characterized by restriction mapping and sequence analysis. By fluorescence in situ hybridization, using the biotinylated genomic clone as a probe, the C/EBP delta gene was assigned to the pericentromeric region of human chromosome 8, most probably to 8q11. This chromosomal localization was confirmed by analysis of a panel of human x hamster somatic cell hybrid DNA samples with a C/EBP delta-specific STS. As a result, the C/EBP delta gene could be positioned between the PLAT and the MOS loci.

Amino Acid Sequence↗

Structure and chromosomal localization of the gene encoding the human myelin protein zero (MPZ).

We describe the cloning, characterization, and chromosomal mapping of the human myelin protein zero (MPZ) gene. The gene is about 7 kb long and consists of six exons corresponding to the functional domains. All exon-intron junction sequences conform to the GT/AG rule. The 5'-flanking region of the gene has a TA-rich element (TATA-like box), two CAAT boxes, and a single defined transcription initiation site detected by the primer extension method. The gene for human MPZ was assigned to chromosome 1q22-q23 by spot blot hybridization of flow-sorted human chromosomes and fluorescence in situ hybridization. The localization of the MPZ gene coincides with the locus for Charcot-Marie-Tooth disease type 1B, determined by linkage analysis.

Base Sequence↗

Structure and chromosomal localization of the aminomethyltransferase gene (AMT)

The gene for human aminomethyltransferase (AMT), also known as the T-protein of the glycine cleavage system, was isolated from a human placental cosmid library and examined by restriction mapping, polymerase chain reaction analysis, and DNA sequencing. The gene is about 6 kb in length and consists of nine exons. The 5'-flanking region of the gene lacks typical TATAA sequence but has a single defined transcription initiation site detected by the primer extension method. Two putative glucocorticoid-responsive elements and a putative thyroid hormone-responsive element are present. The AMT gene was assigned to subband 3p21.2-p21.1 by fluorescence in situ hybridization.

Amino Acid Metabolism, Inborn Errors↗

Structure and chromosomal localization of the gene (BDKRB2) encoding human bradykinin B2 receptor.

The bradykinin B2 receptor (BDKRB2) has high affinity for the intact kinins, which mediate a wide spectrum of biological effects, including pain, inflammation, vasodilation, and smooth muscle contraction and relaxation. In the present study, we have cloned and sequenced the gene encoding human bradykinin B2 receptor from a human genomic library. The B2 receptor gene contains three exons separated by two introns. The first and second exons are noncoding, while the third exon contains the full-length coding region, which encodes a protein of 364 amino acids forming 7 transmembrane domains. The human B2 gene shares high sequence identity with rat and mouse B2 receptor genes and significant similarity with the gene encoding the angiotensin II type I receptor in the nucleotide sequence and exon-intron arrangement. In the 5' flanking region, a consensus TATA box and several putative transcription factor-binding sites have been identified. Genomic Southern blot analysis showed that the B2 receptor is encoded by a single-copy gene that was localized to chromosome 14q32 by in situ hybridization. In a Southern blot analysis following reverse transcription and polymerase chain reaction, the human B2 receptor was found to be expressed in most human tissues.

Amino Acid Sequence↗

The human actin-regulatory protein cap G: gene structure and chromosome location.

Cap G (formerly called macrophage capping protein or gCap39) is a member of the gelsolin/villin family of actin-regulatory proteins. Unlike all other members of this family, Cap G caps the barbed ends of actin filaments, but does not sever them. This protein is half the molecular weight and contains half the number of repeat subunits (3 vs 6) of gelsolin and villin, suggesting that these two proteins may have arisen by gene duplication of the Cap G gene. To investigate this possibility we have cloned and sequenced the human Cap G gene (gene symbol CAPG). The gene is 16.6 kb in size, contains 10 exons and 9 introns, and is located on the proximal short arm of chromosome 2. The open reading frame is 6.9 kb, having 9 exons and 8 introns. This region contains 3 splice sites that are nearly identical to the human gelsolin gene, but shares only one with villin, indicating that CAPG is more closely related to gelsolin. Further comparisons of these three genes, however, indicate that the evolutionary steps resulting in human gelsolin and villin are likely to have been more complex than a simple tandem duplication of the Cap G gene.

Animals↗

Genomic structure and chromosome location of the human mutT homologue gene MTH1 encoding 8-oxo-dGTPase for prevention of A:T to C:G transversion.

8-Oxo-dGTP (8-oxo-7,8-dihydrodeoxyguanosine triphosphate) is produced by active oxygen species in the nucleotide pool of the cell and can be incorporated into cellular DNA. Human cells contain enzyme activity that hydrolyzes 8-oxo-dGTP to 8-oxo-dGMP, thereby preventing occurrence of mutations, caused by misincorporation. When the cDNA for human 8-oxo-dGTPase was expressed in Escherichia coli mutT- mutant cells devoid of self 8-oxo-dGTPase activity, the elevated level of spontaneous A:T to C:G mutation frequency reverted to normal. We isolated the genomic sequence encoding the enzyme and named the gene MTH1 (for mutT human homologue). This gene is composed of at least 4 exons, spans approximately 9 kb, and is located on human chromosome 7p22.

Amino Acid Sequence↗

cDNA sequence, gene structure, and chromosomal localization of the human ATP-sensitive potassium channel, uKATP-1, gene (KCNJ8).

ATP-sensitive K+ (KATP) channels play a crucial role in coupling metabolic energy to the membrane potential of cells. Recently, we have isolated a KATP channel cDNA (uKATP-1) that is expressed ubiquitously in rat tissues including pancreatic islets, pituitary, skeletal muscle, and heart. Here, we report cloning of the human cDNA and gene encoding uKATP-1. Human uKATP-1 is a protein of 424 amino acids exhibiting 98% identity with rat uKATP-1. The human gene encoding uKATP-1, designated KCNJ8, is approximately 9.7 kb in length and is composed of three exons. KCNJ8 was mapped to chromosome 12p11.23 using fluorescence in situ hybridization.

ATP-Binding Cassette Transporters↗

cDNA, gene structure, and chromosomal localization of human GAR1 (CNCG3L), a homolog of the third subunit of bovine photoreceptor cGMP-gated channel.

A unique glutamic acid-rich protein was previously identified in bovine rod photoreceptors (Sugimoto et al., 1991, Proc. Natl. Acad. Sci. USA 88: 3116-3119) and later suggested to be a third subunit (gamma) of the rod cGMP-gated cation channel (Chen et al., 1994, Proc. Natl. Acad. Sci. USA 91: 11757-11761). Here, we report on the characterization of the GAR1 gene encoding a human homolog of bovine gamma. Sequence analysis of cDNA clones encoding human gamma revealed an open reading frame predicting a protein of 299 amino acids (approximately 32 kDa), half the size of the bovine gamma subunit. Comparison of the N-terminal half of bovine gamma with the predicted human gamma sequence revealed 90% identity within the first 31 amino acids, and only 60% homology was found throughout the remainder of the protein sequence. As in bovine gamma, the predicted isoelectric point of the human protein is very acidic despite the absence of the bovine C-terminal glutamic acid-rich domain. The integrity of the cDNA sequence was confirmed by analysis of several overlapping genomic clones that span the GAR1 gene. The protein coding region of the gene consists of 12 exons spanning approximately 11 kb with exon sequence identical to that of the cDNA clones. PCR of somatic cell hybrid DNA with primer pairs that amplify a portion of the GAR1 gene (locus designation CNCG3L) demonstrate localization to chromosome 16. The location of the gene was further delimited by fluorescence in situ hybridization placing the gene at 16q13.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗

Human neuronal pentraxin II (NPTX2): conservation, genomic structure, and chromosomal localization.

We have previously identified a novel rat neuronal member of the pentraxin family (neuronal pentraxin) that may mediate the uptake of synaptic material and the presynaptic snake venom toxin, taipoxin. Here we report human cDNA and genomic sequences of a second neuronal pentraxin. This pentraxin, which we propose to name neuronal pentraxin II (NPII; gene symbol NPTX2), shows 54% amino acid identity to rat neuronal pentraxin (NPI) with 69% identity over the carboxyl-terminal half of NPI and is 88% identical to a newly identified sperm acrosomal pentraxin p50/apexin. Northern blot analysis reveals that NPII message is present in brain, testis, pancreas, liver, heart, and skeletal muscle, so, unlike NPI, NPII is not exclusively localized to neurons. Like NPI, NPII has potential N-linked glycosylation sites. The human NPII gene is 11 kb in length, contains four introns, and is localized to chromosome 7q21.3-q22.1. These data demonstrate the existence of a family of pentraxin proteins that are expressed in the brain and other tissues and that may play important roles in the uptake of extracellular material.

Amino Acid Sequence↗

Structure and chromosomal localization of the human gene of the phosphotyrosyl phosphatase activator (PTPA) of protein phosphatase 2A.

The PTPA gene encodes a specific phosphotyrosyl phosphatase activator of the dimeric form of protein phosphatase 2A. PTPA, cloned from human genomic libraries, is encoded by one single-copy gene, composed of 10 exons and 9 introns with a total length of about 60 kb. The transcription start site was determined, and the 5' flanking sequence was analyzed for its potential as a promotor. This region lacks a TATA sequence in the appropriate position relative to the transcription start, is very GC-rich, and contains upstream of the transcription start four Sp1 sites, a feature common to many TATA-less promotors. Based on the homology with DNA binding consensus sequences of transcription factors, we identified in this promotor region several putative DNA binding sites for transcription factors, such as NF-kappa B, Myb, Ets-1, Myc, and ATF. Transfection experiments with a construct containing the PTPA promotor region inserted 5' of a luciferase reporter gene revealed that the 5' flanking sequence of the PTPA gene indeed displayed promotor activity that seems to be cell-line dependent. By fluorescence in situ hybridization and G-banding, the PTPA gene was localized to the 9q34 region. The PTPA gene is positioned centromeric of c-abl in a region embracing several genes implicated in oncogenesis.

Amino Acid Sequence↗

Gene structure and chromosomal localization of the human HSD11K gene encoding the kidney (type 2) isozyme of 11 beta-hydroxysteroid dehydrogenase.

11 beta-Hydroxysteroid dehydrogenase (11 beta HSD) converts glucocorticoids to inactive products and is thus thought to confer specificity for aldosterone on the type I mineralocorticoid receptor in the kidney. Recent studies indicate the presence of at least two isozymes of 11 beta HSD. In vitro, the NAD(+)-dependent kidney (type 2) isozyme catalyzes 11 beta-dehydrogenase but not reductase reactions, whereas the NADP(+)-dependent liver (type 1) isozyme catalyzes both reactions. We have now characterized the human gene encoding kidney 11 beta HSD (HSD11K). A bacteriophage P1 clone was isolated after screening a human genomic library by hybridization with sheep HSD11K cDNA. The gene consists of 5 exons spread over 6 kb. The nucleotide binding domain lies in the first and the second exon, and the catalytic domain in the fourth exon. The 5' flanking sequences and first exon are GC-rich (80%), suggesting that the gene may be transcriptionally regulated by factors that recognize GC-rich sequences. Fluorescence in situ hybridization of metaphase chromosomes with a positive P1 clone localized the gene to chromosome 16q22. In contrast, the HSD11L (liver isozyme) gene is located on chromosome 1 and contains 6 exons; the coding sequences of these genes are only 21% identical. HSD11K is expressed at high levels in the placenta and kidney of midgestation human fetuses and at lower levels in lung and testes. Different transcriptional start sites are utilized in kidney and placenta. These data should be applicable to genetic analysis of the syndrome of apparent mineralocorticoid excess, which may represent a deficiency of 11 beta HSD.

11-beta-Hydroxysteroid Dehydrogenases↗

Structure and chromosomal localization of the GPI-anchor synthesis gene PIGF and its pseudogene psi PIGF.

Posttranslational modification by the GPI glycolipid anchor is essential for the surface expression of many membrane proteins. Defect of GPI biosynthesis due to somatic mutation in the hematopoietic stem cell is the basis for an acquired genetic disease, paroxysmal nocturnal hemoglobinuria (PNH). Previously, an X-linked gene PIGA (phosphatidylinositol glycan class A), which participates in the first step of the biosynthesis, was shown to be mutated in abnormal cells from all 60 patients with PNH. The cDNA of another GPI synthesis gene PIGF was previously cloned, but it is not involved in pathogenesis of PNH. In the present study, we have analyzed PIGF genomic clones. The PIGF gene contained six exons spanning about 40 kb and was located to the short arm of chromosome 2 at 2p16-p21. The frequency of mutations on both alleles of PIGF should be much lower than that of mutation in the X-linked PIGA, accounting for a lack of involvement of PIGF in PNH. We also identified the processed pseudogene of PIGF (psi PIGF) and mapped it to 5q35.

Base Sequence↗

Structure and chromosomal localization of the human salivary mucin gene, MUC7.

We have isolated and characterized several MUC7 genomic clones encoding the human low-molecular-weight salivary mucin, MG2. The MUC7 gene spans approximately 10.0 kb and comprises of three exons and two introns. Intron 1 is approximately 1.7 kb long and is located in the 5'-untranslated region of the corresponding MUC7 cDNA. Intron 2 spans approximately 6.0 kb and is located close to the boundary of the putative leader peptide and secreted protein. The entire region encoding the secreted peptide is located on exon 3, spanning approximately 2.2 kb. The nucleotide sequence of sections of the MUC7 gene, including 1500 bp of the 5'-flanking region, was determined and analyzed for motifs identical or homologous to other known response elements. A modified RACE procedure was used to determine the 5'-end of the MUC7 mRNA. PCR, the human-hamster somatic cell hybrid panel PCRable DNAs kit, and an in situ hybridization analysis on the complete metaphase chromosome spreads were used for the chromosomal localization of the MUC7 gene. It was mapped to chromosome 4q13-q21.

Animals↗

Genomic structure and chromosomal mapping of the mouse VE-cadherin gene (Cdh5).

Vascular endothelial cadherin (VE-cadherin) is located strictly at endothelial junctions and appears to be a major adhesive component of cell to cell contacts. Genomic clones spanning 36 kb and encompassing the mouse VE-cadherin gene have been isolated and characterized. The gene is composed of 12 exons that exhibit conventional vertebrate splicing. The first exon is entirely untranslated, and both exons 2 and 12 contain untranslated regions. A single major transcriptional start site was identified and located 75 bases upstream of the translation initiation codon in the cDNA sequence. The proximal 5'-flanking domain lacks consensus TATA and CAAT boxes at the usual positions. Exon-intron boundaries are similar to those of other cadherin genes, with some exceptions that may have a functional significance in VE-cadherin behavior. The VE-cadherin gene (locus Cdh5) maps to mouse chromosome 8, where it colocalizes with E-cadherin (locus Cdh1), P-cadherin (locus Cdh3), and M-cadherin (locus Cdh14) genes, suggesting that it might be part of a larger cluster of cadherin sequences.

Amino Acid Sequence↗

Structure and chromosomal localization of the human prostasin (PRSS8) gene.

Prostasin, denoted as PRSS8, is a newly identified human serine proteinase that shares high sequence identity with acrosin, plasma kallikrein, and hepsin (Yu et al., 1994, 1995). In the present study, a full-length PRSS8 gene has been isolated and characterized. A 7-kb PRSS8 gene fragment has been sequenced, including a 1.4-kb 5'-flanking region, the 4.4-kb PRSS8 gene, and a 1.2-kb 3'-flanking region. The gene consists of six exons and five introns based on comparison with its cDNA sequence. The sizes of these exons are 417, 18, 163, 272, 167, and 899 bp, while those of the introns are 243, 1763, 271, 85, and 92 bp. A number of potential regulatory elements have been revealed in the 5'-flanking region, including an AP2 site, two erythroid-specific promoter elements, and a sterol regulatory element. In addition, there are a variant GC box and a variant AP1 site in the promoter region. The transcription initiation site of the PRSS8 gene has been defined at the G residue and its adjacent A residue in a sequence CTCATGACT, which is similar to an initiator element CTCANTCT. Between the transcription initiation site and these putative regulatory elements, there is an AC-rich repetitive sequence that spans over 300 bp. Human PRSS8 is a single-copy gene and has been localized on chromosome 16p11.2 by in situ hybridization.

Amino Acid Sequence↗