Localization of the intronless gene coding for calmodulin-like protein CLP to human chromosome 10p13-ter

The functional intronless gene coding for a calmodulin-like protein (CLP) has been localized to human chromosome 10p13-ter. Chromosomal assignment was performed by Southern blot analysis of DNA from human-rodent somatic cell hybrids and amplification of a CLP gene-specific 1090-bp DNA fragment by the polymerase chain reaction (PCR) on DNA from human-hamster cell hybrids. Chromosomal sublocalization was carried out by in situ hybridization of human chromosome metaphase spreads. The CLP gene is the first member of the human calmodulin/calmodulin-like gene family to be chromosomally sublocalized. Its presence near the telomeric end of the short arm of chromosome 10 may be of significance with respect to its highly (epithelial) cell-type restricted expression in vivo and strong downregulation upon malignant transformation. The generation of a human CLP gene-specific sequence tag site specified by the two primers used for PCR should prove useful for future linkage studies.     

Identification of a new P450 expressed in human lung: complete cDNA sequence, cDNA-directed expression, and chromosome mapping

A cDNA coding for a P450 expressed in human lung was isolated from a lambda gt11 library constructed from human lung mRNA using a cDNA probe to rat P450 IVA1. The cDNA-deduced amino acid sequence of this P450, designated IVB1, consisted of 511 amino acids and had a calculated molecular weight of 59,558. The IVB1 amino acid sequence bore 51%, 53%, and 52% similarities to rat IVA1, IVA2, and rabbit P450p-2, respectively. Comparison of the primary amino acid sequence of human IVB1 with rat IVA and rabbit p-2 P450 sequences revealed a region of absolute sequence identity of 17 amino acids between residues 304 and 320. However, the functional significance of this conserved sequence is unknown. Human IVB1 also appears to be related to P450 isozyme 5 that has been extensively characterized in rabbits. The IVB1 cDNA was inserted into a vaccinia virus expression vector and the enzyme expressed in human cell lines. The expressed enzyme had an absorption spectrum with a lambda max at 450 nm when reduced and complexed with carbon monoxide, typical of other cytochrome P450s. Unlike rabbit P450 isozyme 5, however, human IVB1 was unable to activate the promutagen 2-aminofluorene. Human lung microsomal P450s were also unable to metabolize this compound despite the presence of IVB1 mRNA in three out of four human lungs analyzed. In contrast to its expression in lung, IVB1 mRNA was undetectable in livers from 14 individuals, including those from which the lungs were derived. IVB1-related mRNA was also expressed in rat lung and was undetectable in untreated rat liver.(ABSTRACT TRUNCATED AT 250 WORDS)     

In situ mapping of the muscle-specific form of phosphoglycerate mutase gene to human chromosome 7p12-7p13

Summary A 2.3-kb-long probe derived from the 5 flanking region, the first exon and part of the first intron of the human muscle-specific phosphoglycerate mutase gene (PGAM-M) (EC 5.4.2.1) was used to map the gene by in situ chromosomal hybridization. The structural gene for PGAM-M was assigned to chromosome 7p12-7p13; a single hybridization peak indicated that there is a single gene for this isozyme of PGAM, and confirmed results obtained by Southern blot hybridization.     

PALML, a novel paralemmin-related gene mapping on human chromosome 1p21.

We describe PALML, a novel gene encoding a 551 amino acid protein with similarity to paralemmin and the paralemmin-like amino terminal domain of AKAP2, a protein kinase A anchor protein. PALML mRNA is expressed in many tissues and is most abundant in cardiac and skeletal muscle, while absent from brain and blood. Exogenously expressed PALML fusion protein has a widespread cytoplasmic localization, and it is excluded from the nucleus. Human PALML maps on human chromosome 1p21 (between D1S2767 and D1S223). SSCP-HD analysis of exonic sequences in patients with VUR (familial non-syndromic vesicoureteral reflux syndrome) excluded mutations in the PALML gene from causing this disease. PALML, paralemmin and AKAP2 share the presence of a conserved coiled coil region that may mediate protein interactions with shared partners. Based on its resemblance to paralemmin and AKAP2, PALML is hypothesized to be involved in regulating intracellular signaling and membrane-cytoskeletal interactions.     

The gene for the human putative apoE receptor is on chromosome 12 in the segment q13-14

We have previously described the cDNA coding for a new lipoprotein receptor that contains domains closely related to the ligand-binding domain of the LDL receptor. We have now investigated the localization of the gene for this new receptor by hybridization of the cDNA to panels of rodent cells containing subsets of human chromosomes and by in situ hybridization of the cDNA to chromosomes. The gene maps to 12q13-14, a known hot spot for chromosomal rearrangements in human neoplasia. Of particular interest is the frequent involvement of the 12q13-14 segment in clonal abnormalities in lipomas and myxoid liposarcomas, and it is possible that LRP may play a role in the pathogenesis of such tumors.     

A gene cluster encoding human epidermis-type lipoxygenases at chromosome 17p13.1: cloning, physical mapping, and expression

Epidermis-type lipoxygenases, a distinct subclass within the multigene family of mammalian lipoxygenases (LOX), comprise recently discovered novel isoenzymes isolated from human and mouse skin including human 15-LOX-2, human and mouse 12R-LOX, mouse 8S-LOX, and mouse e-LOX-3. We have isolated the human homologue of mouse e-LOX-3. The cDNA of 3362 bp encodes a 711-amino-acid protein displaying 89% sequence identity with the mouse protein and exhibiting the same unusual structural feature, i.e., an extra segment of 41 amino acids, which can be located beyond the N-terminal beta-barrel domain at the surface of the C-terminal catalytic domain. The gene encoding e-LOX-3, ALOXE3, was found to be part of a gene cluster of approximately 100 kb on human chromosome 17p13.1 containing in addition the 12R-LOX gene, ALOX12B, the 15-LOX-2 gene, ALOX15B, and a novel 15-LOX pseudogene, ALOX15P. ALOXE3 and ALOX12B are arranged in a head-to-tail fashion separated by 8.5 kb. The genes are split into 15 exons and 14 introns spanning 22 and 15 kb, respectively. ALOX15P was found on the opposite DNA strand directly adjacent to the 3'-untranslated region of ALOX12B. ALOX15B is located in the same orientation 25 kb downstream of ALOX12B, and is composed of 14 exons and 13 introns spanning a total of 9.7 kb of genomic sequence. RT-PCR analysis demonstrated a predominant expression of ALOXE3, ALOX12B, and ALOX15B in skin.     

Regulation of rRNA gene expression in a human familial 14p+ marker chromosome

Summary Chromosome studies were carried out on normal individuals from three generations of one family with a 14p+ chromosome. The short arm of the 14p+ chromosome stained well using Giemsa but poorly using quinacrine or trypsin-Giemsa methods; in each case there was an unstained secondary constriction near the distal end of the short arm. Two Ag bands of average size were present on the 14p+ short arm, indicating that there were two active nucleolus organizer regions; the Ag band near the distal end of the short arm was slightly larger than that near the centromere. Each of the two Ag bands was seen associated with the short arm of one or more of the other acrocentric chromosomes, with a combined frequency of association no greater than that of other chromosomes with an Ag band of the same size. In one individual, hybridization in situ with radioactive 18S and 28S ribosomal RNA showed six times as many autoradiographic silver grains over the short arm of the 14p+ chromosome as over that of any other acrocentric chromosome. The results obtained using in situ labeling indicated that the 14p+ chromosome had a large number of rRNA genes compared with the other acrocentric chromosomes, whereas the results obtained using Ag-staining and association frequency indicated that the 14p+ chromosome had no greater nucleolus organizer activity than did the other acrocentrics. The difference in these findings suggests that not all the rRNA genes on the 14p+ chromosome were active.     

The gene coding for a sphingolipid activator protein,SAP-1, is on human chromosome 10

Summary SAP-1 is a sphingolipid activator protein found in human tissues required for the enzymatic hydrolysis of GM1 ganglioside and sulfatide. It appears to be missing in patients who have a genetic lipidosis resembling juvenile metachromatic leukodystrophy. Using rabbit antibodies against human SAP-1 it could be visualized in extracts from cultured human skin fibroblasts after sodium dodecylsulfate-polyacrylamide gel electrophoresis, followed by electroblotting to nitrocellulose membrane and immunochemical staining (Western blotting). A series of 23 human-Chinese hamster ovary cell hybrids containing different human chromosomes were examined. The parent Chinese hamster ovary cells did not have a reacting protein in the region of human SAP-1. Only in the eight hybrid clones containing human chromosome 10 was a reacting protein identified. Other chromosomes were excluded by this method. Therefore the gene for SAP-1 and the genetic mutation resulting in a fatal lipidosis are located on human chromosome 10. Present address: Department of Pediatrics, Osaka University Medical School, Fukushima-Ku, Osaka, Japan     

The complete coding sequence of the human raf oncogene and the corresponding structure of the c-raf-1 gene.

The complete 648 amino acid sequence of the human raf oncogene was deduced from the 2977 nucleotide sequence of a fetal liver cDNA. The cDNA has been used to obtain clones which extend the human c-raf-1 locus by an additional 18.9 kb at the 5' end and contain all the remaining coding exons.     

Reassignment of the human macrophage colony stimulating factor gene to chromosome 1p13-21.

Macrophage colony stimulating factor (CSF-1) is a member of a family of glycoproteins that are necessary for the normal proliferation and differentiation of myeloid progenitor cells. The human CSF-1 gene has previously been assigned to chromosome 5 using somatic cell hybrids, and further localized to 5q33 by in situ hybridization with a 3H labelled cDNA probe. However, the murine macrophage colony stimulating factor gene (csfm) has been localized to a region on mouse chromosome 3 which was previously shown to be syntenic with the proximal region of 1p and not 5q. Using a human genomic DNA clone that contains the CSF-1 gene, we have localized CSF-1 to chromosome 1p13-21 by fluorescence in situ hybridization. The reassignment of the CSF-1 gene argues against its involvement in myeloid disorders with deletions of the long arm of chromosome 5.     

The gene coding for the human T-lymphocyte CD2 antigen is located on chromosome 1p

Summary A cDNA clone encoding the human T lymphocyte sheep erythrocyte receptor [the CD2 (T11) antigen] was used as a probe to define the chromosomal location of the gene. The signal, revealed by hybridisation to Southern blots of genomic DNA from somatic cell hybrids, showed a high degree of concordance for human chromosome 1. In particular, the hybrid F4Sc13C19 which contained the short arm only of human chromosome 1 was positive. The location of the CD2 gene to 1p13 was confirmed by in situ hybridisation.