Chromosomal assignment of human uracil-DNA glycosylase to chromosome 12

Using Southern blot analysis of DNA from a panel of rodent-human somatic cell hybrids with known karyotypes, we have assigned the human uracil-DNA glycosylase gene to chromosome 12.     

A human gene coding for a membrane-associated nucleic acid-binding protein

Studies to clone a cell-surface DNA-binding protein involved in the binding and internalization of extracellular DNA have led to the isolation of a gene for a membrane-associated nucleic acid-binding protein (MNAB). The full-length cDNA is 4.3 kilobases with an open reading frame of 3576 base pairs encoding a protein of approximately 130 kDa (GenBank accession numbers and ). The MNAB gene is on human chromosome 9 with wide expression in normal tissues and tumor cells. A C3HC4 RING finger and a CCCH zinc finger have been identified in the amino-terminal half of the protein. MNAB bound DNA (K(D) approximately 4 nm) and mutagenesis of a single conserved amino acid in the zinc finger reduced DNA binding by 50%. A potential transmembrane domain exists near the carboxyl terminus. Antibodies against the amino-terminal half of the protein immunoprecipitated a protein of molecular mass approximately 150 kDa and reacted with cell surfaces. The MNAB protein is membrane-associated and primarily localized to the perinuclear space, probably to the endoplasmic reticulum or trans-Golgi network. Characterization of the MNAB protein as a cell-surface DNA-binding protein, critical in binding and internalization of extracellular DNA, awaits confirmation of its localization to cell surfaces.     

Chromosomal localization of the gene for a human thyroid hormone-binding protein.

A cDNA for the gene that encodes for a human cellular thyroid hormone-binding protein (p55) has recently been isolated and sequenced. The sequence of p55 indicates that it is identical to the protein disulfide isomerase and the beta-subunit of prolyl 4-hydroxylase. By in situ hybridization, the gene for p55 was localized on chromosome 17 at band q25. This localization shows that the p55 gene is not linked to either erbA1 or erbA2; two other thyroid hormone-binding protein genes are located at 17q 11-21 and 3p21-pter, respectively. The localization of p55 gene will permit the evaluation of the possible effects of chromosome changes on the structure and activity of the p55 gene in chromosome syndromes or neoplasms.     

Chromosomal localization of the human elastin gene.

mRNA isolated from fetal human aorta was used to synthesize cDNA that was cloned into the PstI site of pBR322. The recombinant clones were screened with an authentic sheep elastin cDNA, and one human clone that hybridized strongly was isolated and characterized. The 421-base pair (bp) insert of this human clone was sequenced by the dideoxy method, and the DNA sequence showed strong homology to the nontranslated portion of the sheep elastin cDNA. This result unequivocally identified the human clone, designated pcHEL1, as an elastin clone. Plasmid pcHEL1 labeled with [3H] nucleotides was used in in situ hybridization experiments utilizing normal metaphase chromosomes and also with cells carrying a balanced translocation between chromosomes 1 and 2: 46,XY,t(1;2)(p36;q31). The results strongly suggest that the elastin gene is localized to the q31----qter region of chromosome 2.     

Chromosomal assignment of the human smg GDP dissociation stimulator gene to human chromosome 4q21-q25

The 3-end of the cDNA encoding the smg GDP dissociation stimulator (smg GDS) protein shares 100% homology with the previously published expressed sequence tag 00038 site. This site extends the 3-end of the smg GDS gene by 212 bp. It has been localized to human chromosome 4. Here, we have refined the localization of smg GDP to human chromosome 4q21-q25 using a mapping panel of rodent/human somatic cell hybrids containing different parts of chromosome 4. This chromosomal localization of smg GDP to 4q21-25 overlaps with a region of allele loss in primary hepatocellular carcinoma (4q13-q26).HGM symbol: RAP1GDS1     

Chromosomal localization of a cytochrome b5 gene to human chromosome 18 and a cytochrome b5 pseudogene to the X chromosome.

We have isolated cDNA clones that code for human cytochrome b5. Owing to the high degree of evolutionary conservation of cytochrome b5 sequences and the existence of human and rodent cytochrome b5 processed pseudogenes, we were unable to map unambiguously the chromosomal localization of the human gene(s) by Southern blot hybridization of DNA from human-rodent somatic cell hybrids. An alternative approach, based on restriction enzyme digestion of PCR-amplified DNA, enabled us to map the human cytochrome b5 gene(s) to chromosome 18 and one of its processed pseudogenes to the X chromosome. We propose the designations CYB5 and CYB5P1 for the gene and pseudogene loci, respectively.     

Chromosomal assignment of a novel human gene D40.

We have previously reported an identification of a novel human cellular factor, D40. Here, we report the chromosomal localization of the gene that encodes D40. Fluorescent in situ hybridization (FISH) was performed to determine the chromosomal region that D40 gene resides. The chromosomes that derived from normal adult male lymphocytes were hybridized with a mixture of cDNA probes that cover the entire coding region of D40. D40 gene mapped to the long arm of chromosome 15q14-15.     

Chromosomal assignment of the human immunophilin FKBP-12 gene

FKBP-12 is the major T cell binding protein for the immunosuppressive drugs FK506 and rapamycin. It is a member of the immunophilin family of proteins which are believed to play a role in immunoregulation and basic cellular processes involving protein folding and trafficking. The chromosomal assignment of the human FKBP-12 gene was determined by using the polymerase chain reaction to amplify an intron-containing region of the gene in purified DNA isolated from 42 human-rodent somatic cell hybrids. The results of this analysis indicated that the FKBP-12 gene resides on human chromosome 20.     

Chromosomal assignment of the murine gene encoding the transformation-related protein p53.

p53 is a transformation-related protein that is encoded by the cellular genome and is synthesized at elevated levels in a wide range of different cell line types and in primary tumors of various species. By using several independently established anti-p53 monoclonal antibodies, it was possible to distinguish between p53 of mouse origin and p53 of Chinese hamster origin. By analysis of a series of mouse X Chinese hamster hybrid cell lines containing various mouse chromosomes, we mapped the p53 gene product to mouse chromosome 11.     

The inhibition of nucleic acid-binding proteins by aurintricarboxylic acid

Qβ replicase, $\text{Escherichia coli}$ RNA polymerase, and T7 RNA polymerase are inhibited by low concentrations of the dye aurintricarboxylic acid (ATA). In each case initiation by the enzyme was preferentially inhibited. The elongation of initiated polynucleotide chains by Qβ replicase was insensitive to ATA in the range of concentrations required to inhibit initiation. Treatment of Qβ replicase, RNA polymerase and $\text{lac}$ repressor with ATA prevented enzymemediated binding of the templates to nitrocellulose filters. We propose that the inhibitor combines with the template binding site of these proteins to prevent initiation.     

Molecular analysis of human complement component C5: localization of the structural gene to chromosome 9

A human C5 clone (pC5HG2) was isolated from a cDNA library constructed from Hep G2 mRNA. The DNA sequence showed that the pC5HG2 insert was comprised of 3309 base pairs of pro-C5 coding sequence and 404 base pairs of 3'-untranslated sequence. The derived amino acid sequence contained the entire coding sequence of the C5 alpha-chain, the beta-alpha-chain junction region, and 100 amino acids (approximately 50%) of the beta-chain. Protein sequences of four C5 tryptic peptides were aligned exactly to this sequence and demonstrated that C5 synthesized and secreted by Hep G2 cells is probably identical with plasma-derived C5. Coding sequence alignment of the human C5 sequences with those of murine C5 indicated that 80% of the nucleotides and 79% of the amino acids were placed identically in the two species. Amino acid sequence alignment of the homologous family members C3, C4, and alpha 2-macroglobulin with that of C5 demonstrated 27%, 25%, and 19% identity, respectively. As was found in murine C5, the corresponding thiol ester region of human C5 contained several conserved amino acids, but the critical cysteine and glutamine residues which give rise to the intramolecular thiol ester bond in C3, C4, and alpha 2-macroglobulin were absent in C5, having been replaced by serine and alanine, respectively. With the use of a panel of hamster-human somatic cell hybrids, the C5 gene was mapped to human chromosome 9. In situ chromosomal hybridization studies employing metaphase cells further localized the gene to bands 9q32-34, with the largest cluster of grains at 9q34.1.     

cDNA cloning of human oxysterol-binding protein and localization of the gene to human chromosome 11 and mouse chromosome 19

Cellular cholesterol metabolism is regulated primarily through sterol-mediated feedback suppression of the activity of the low-density lipoprotein receptor and several enzymes of the cholesterol biosynthetic pathway. We previously described the cloning of a rabbit cDNA for the oxysterol-binding protein (OSBP), a cytosolic protein of 809 amino acids that may participate in these regulatory events. We now use the rabbit OSBP cDNA to clone the human OSBP cDNA and 5' genomic region. Comparison of the human and rabbit OSBP sequences revealed a remarkably high degree of conservation. The cDNA sequence in the coding region showed 94% identity between the two species, and the predicted amino acid sequence showed 98% identity. The human cDNA was used to determine the chromosomal localization of the OSBP gene by Southern blot hybridization to panels of somatic cell hybrid clones containing subsets of human or mouse chromosomes and by RFLP analysis of recombinant inbred mouse strains. The OSBP locus mapped to the long arm of human chromosome 11 and the proximal end of mouse chromosome 19. Along with previously mapped genes including Ly-1 and CD20, OSBP defines a new conserved syntenic group on the long arm of chromosome 11 in the human and the proximal end of chromosome 19 in the mouse.     

cDNAs encoding members of a family of proteins related to human sterol carrier protein 2 and assignment of the gene to human chromosome 1 p21----pter.

Sterol carrier protein 2 (SCP2) is believed to play a key role in intracellular lipid movement. Here we report the cloning and nucleotide sequences of cDNAs encoding SCP2-related proteins of 58.85 kD and 30.8 kD and the assignment of the SCP2 gene to human chromosome 1 p21-pter. The SCP2-related proteins share common deduced carboxyl amino acid sequences with SCP2 and the cDNAs have a common 3' untranslated nucleotide sequence. The mRNAs encoding these proteins increased in a coordinate fashion as human placental cytotrophoblasts differentiated into syncytiotrophoblasts in culture. Our observations document the existence of a family of related proteins encoded by the human SCP2 gene.     

The human hedgehog-interacting protein gene: structure and chromosome mapping to 4q31.21-->q31.3.

Hedgehog-interacting protein (Hhip) is a novel regulatory component in the vertebrate hedgehog-signalling pathway. The murine Hhip encodes a type I TM protein that attenuates hedgehog signalling by binding all three mammalian hedgehog proteins. Here we describe the cloning and characterisation of the homologous human hedgehog-interacting protein gene (HHIP). HHIP comprises 13 exons and spans >91kb encoding a protein of 700 aa which shares 94% sequence iden- tity with mouse Hhip. HHIP maps to chromosome 4q31.21--> q31.3. Additionally, we have mapped murine Hhip to chromosome 8.     

Chromosomal mapping of the human catechol-O-methyltransferase gene to 22q11.1----q11.2.

Catechol-O-methyltransferase (COMT; EC 2.1.1.6) is a physiologically important enzyme in the metabolism of catecholamine neurotransmitters and catechol drugs. Using primers derived from the known rat cDNA sequence for COMT, we have used the polymerase chain reaction to produce an amplified DNA fragment corresponding to the complete coding region of the rat gene. With this fragment as a probe, we have hybridized DNAs from two panels consisting of human/rodent and human/hamster somatic cell hybrids carrying various translocations and deletions to refine the chromosomal location of human COMT. Southern blot analysis indicates that the human COMT gene is localized to 22q11.1----q11.2, a region to which several anonymous DNA sequences, but until now, no structural genes, have been assigned.