Regional assignment of human genes TPI1, GAPDH, LDHB, SHMT, and PEPB on chromosome 12.

Karyological analysis was performed on a series of human-Chinese hamster cell hybrids containing deletions of human chromosome 12. Chromosome breakage was produced by treatment of the cells with either X-rays or 5-bromodeoxyuridine and near-visible light. The hybrid clones were analyzed for the presence or absence of the following five human gene markers known to be located on chromosome 12: triosephosphate isomerase-1 (TPI1), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), lactate dehydrogenase-B (LDHB), serine hydroxymethyltransferase (SHMT), and peptidase-B (PEPB). Based on the correlation between the isozyme markers and karyological analysis of these clones, a regional map of the five human genes on chromosome 12 was established. The linear order for these genes is: pter-TPI1-GAPDH-LDHB-centromere-SHMT-PEPB-qter. The locations of these genes are: TPI1, GAPDH, LDHB: pter leads to p12; SHMT: q12 leads to q14; PEPB: q14 leads to qter. Statistical analysis similar to that of Goss and Harris (1975, 1977a, b) has been performed on the segregation data in the hybrid clones. The statistical map, in general, agrees with the cytogenetic map and further localizes PEPB to 12q21.     

Chromosomal assignment and regional localization of myeloperoxidase in the mouse

Using a rat x mouse somatic cell hybrid that contains chromosome 11 as the only mouse material, we have shown that myeloperoxidase, which maps to human chromosome 17, maps to mouse chromosome 11. Regional assignment of the gene by in situ hybridization localized Mpo to the region C-E1, with a peak at band 11C. These results further confirm and extend observations on the remarkable homology between human chromosome 17 and mouse 11.     

Further data on chromosomal assignments of pig enzyme loci LDHA, LDHB, MPI, PEPB and PGM1, using somatic cell hybrids

Clear interspecies differentiation between the chromosomes in pig-mouse somatic cell hybrids was achieved by using the THA-technique for the cytogenetic analysis. The assignments of LDHB and MPI to pig chromosomes nos 5 and 7 respectively, reported previously, were confirmed by analysis of 34 hybrid clones. The LDHA, PEPB and PGM1 genes were assigned to pig chromosomes nos 2, 5 and 6 respectively. Both LDHB and PEPB were indicated to be located on the long arm, except the most proximal part, of pig chromosome no. 5. The proposed synteny between LDHB and PEPB in pigs is in accordance with the synteny observed between these two loci in several other mammalian species.     

Further data on chromosomal assignments of pig enzyme loci LDHA, LDHB, MPI, PEPB and PGM1, using somatic cell hybrids

Summary. Clear interspecies differentiation between the chromosomes in pig-mouse somatic cell hybrids was achieved by using the THA-technique for the cytogenetic analysis. The assignments of LDHB and MPI to pig chromosomes nos 5 and 7 respectively, reported previously, were confirmed by analysis of 34 hybrid clones. The LDHA, PEPB and PGM1 genes were assigned to pig chromosomes nos 2, 5 and 6 respectively. Both LDHB and PEPB were indicated to be located on the long arm, except the most proximal part, of pig chromosome no. 5. The proposed synteny between LDHB and PEPB in pigs is in accordance with the synteny observed between these two loci in several other mammalian species.     

Direct assignment of citrate synthase (CS) gene to human chromosome 12 in man-mouse somatic cell hybrids

Summary A panel of twenty independently derived clones of man-mouse somatic cell hybrids isolated from fusions involving eight different parent cell combinations simultaneously analyzed for human chromosomes, citrate synthase, and a large number of other enzyme markers firmly or tentatively assigned to individual human chromosomes have provided direct evidence for a firm assignment of the structural gene coding for citrate synthase (CS) to human chromosome 12.     

Chromosomal assignment of 11 loci in the rat by mouse-rat somatic hybrids and linkage

Eleven rat genes have been assigned to rat chromosomes by use of mouse × rat somatic hybrids and/or use of linkage to known chromosome markers. Among them, the genes for the inducible nitric oxide synthase (Nos2) and for a vasoactive intestinal peptide receptor (Vipr) are potential candidates for genetic regulation of blood pressure and were localized to rat Chromosomes (Chrs) 10 and 8 respectively. Genes for gastric H,K-ATPase alpha subunit (Atp4a). Class I alcohol dehydrogenase (Adh), and aldolase C (Aldoc) were localized to Chrs 1, 2, and 10 respectively, and thus provide more DNA markers for genetic mapping of quantitative trait loci for blood pressure on those chromosomes. Genes for alkaline phosphatase (Alp1) and cardiac AE-3 Cl^-/HCO₃ ^- exchanger (Ae3) were both localized to Chr 9. Genes for glutamate dehydrogenase (Glud) and gastric H,K-ATPase beta subunit (Atp4b) were localized to Chr 16. The ornithine decarboxylase (Odc) gene and ornithine decarboxylase pseudogene (Odcp) were localized to Chrs 6 and 11 respectively.     

Expression of the human adenylate kinase isozymes,phosphopyruvate hydratase, 6-phosphogluconate dehydrogenase,and phosphoglucomutase-1 in man-rodent somatic cell hybrids

The expression of the adenylate kinase isozymes and of phosphopyruvate hydratase was studied in man-mouse and man-hamster hybrid clones. Concordant segregation of the loci coding for AK-2 and PPH was observed in 54 of 55 primary hybrid clones, and these loci were demonstrated to be synthetic with the loci specifying PGM-1 and PGD. The pattern of expression of the four enzymes in discordant clones suggests the gene order 1pter-(PGD,PPH)-AK-2-PGM-1-centromere. In addition, AK-1 was found to be expressed independently of AK-2.This work was supported by the NIH Grants 5 PO1 HB 06276-04, HD 04807-06, and HD 06285-04.     

A new immunochemical method for the quantitative measurement of specific gene products in man-rodent somatic cell hybrids

Summary An immunochemical method has been developed for the quantitative determination of species-specific gene products, for instance a-galactosidase and N-acetyl-a-galactosaminidase, in man-rodent hybrid cells and in the parental cell lines. Antisera raised against the purified enzymes are covalently coupled to Sepharose 4B. The gene products are specifically removed from a cell lysate by incubating with the appropriate Sepharose-coupled antiserum. After centrifugation followed by washing of the precipitated Sepharose, the enzymic activity can be quantitatively measured on the Sepharose beads. With this technique it has been demonstrated that the ability of human N-acetyl-a-galactosaminidase (also known as a-galactosidase B) to hydrolyze a-galactosidic linkages is lost when the enzyme is expressed in man-Chinese hamster hybrid cells.     

Human beta interferon gene localization and expression in somatic cell hybrids.

The human fibroblast interferon gene beta 1 was mapped to human chromosome 9. Sequence homology with a beta 1 cDNA clone was detected in both genomic DNA and induced mRNA of human/mouse or human/hamster somatic cell hybrids containing human chromosome 9, but not in lines lacking this chromosome or those retaining a complex translocation involving chromosomes 9 and 11. Interferon mRNA that did not share sequence homology with the beta 1 cDNA clone was detected in lines containing human chromosomes 2 and 5 but lacking chromosome 9, suggesting the presence of other unlinked interferon sequences in the human genome.     

Chromosomal localization of rDNA in the Brassicaceae.

A survey is given about the number and chromosomal position of rDNA loci in 45 Brassicaceae species. For 34 species, 5S and 45S rDNA loci have been localized by two-colour fluorescence in situ hybridization for the first time. These data show the variability of rDNA within karyotypes of the Brassicaceae, provide anchor points for (comparative) genetic maps, and might be important for studies on concerted evolution of internal transcribed sequence types of rDNA in cruciferous plants.     

Purification, properties and cellular localization of the stereospecific CS2 secondary alkylsulphohydrolase of Comamonas terrigena.

The availability of homogeneous samples of the potassium salts of L- and D-octan-2-yl sulphate has enabled the separation of the optically stereospecific CS1 and CS2 secondary alkysulphohydrolases from extracts of cells of Comamonas terrigena. The CS2 enzyme was purified to homogeneity, and an initial study was made of its general properties, specificity, cellular localization and relationship to the CS1 enzyme. The CS2 enzyme has a molecular weight of approx. 250000 and a subunit size of approx. 58000, indicating that the molecule is a tetramer. Under the experimental conditions used the enzyme appears to be specific for (+)-secondary alkyl sulphate esters with the sulphate group at C-2 and with a chain length of at least six carbons. Enzyme activity towards racemic C-2 sulphates increases with increasing chain length up to C10, and there is some indirect evidence to suggest that activity declines when that chain length is exceeded. Other indirect evidence confirms that the CS1 enzyme exhibits similar specificity, except that only (-)-isomers can serve as substrates. Both enzymes are present in broth-grown stationary-phase cells of C. terrigena in approximately equal amounts.     

Chromosomal assignment of the genes for human aldehyde dehydrogenase-1 and aldehyde dehydrogenase-2.

Chromosomal assignment of the genes for two major human aldehyde dehydrogenase isozymes, that is, cytosolic aldehyde dehydrogenase-1 (ALDH1) and mitochondrial aldehyde dehydrogenase-2 (ALDH2) were determined. Genomic DNA, isolated from a panel of mouse-human and Chinese hamster-human hybrid cell lines, was digested by restriction endonucleases and subjected to Southern blot hybridization using cDNA probes for ALDH1 and for ALDH2. Based on the distribution pattern of ALDH1 and ALDH2 in cell hybrids, ALDH1 was assigned to the long arm of human chromosome 9 and ALDH2 to chromosome 12.     

Chromosomal and regional localization of the genes for UMPH2, APRT, PEPD, PEPS, PSP, and PGP in mink: comparison with man and mouse

Segregation of mink biochemical markers uridine 5'-monophosphate phosphohydrolase-2 (UMPH2), adenine phosphoribosyltransferase (APRT), phosphoserine phosphatase (PSP), phosphoglycolate phosphatase (PGP), peptidases D (PEPD) and S (PEPS), as well as mink chromosomes, was investigated in a set of mink x mouse hybrid clones. The results obtained allowed us to make the following mink gene assignments: UMPH2, chromosome 8; PEPD and APRT, chromosome 7; PEPS, chromosome 6; and PSP and PGP, chromosome 14. The latter two genes are the first known markers for mink chromosome 14. For regional mapping, UMPH2 was analyzed in mouse cell clones transformed by means of mink metaphase chromosomes (Gradov et al., 1985) and also in mink x mouse hybrid clones carrying fragments of mink chromosome 8 of different sizes. Based on the data obtained, the gene for UMPH2 was assigned to the region 8pter----p26 of mink chromosome 8. The present data is compared with that previously established for man and mouse with reference to the conservation of syntenic gene groups and G-band homoeologies of chromosomes in mammals.     

Regional localization of DNA sequences on chromosome 21 using somatic cell hybrids.

We have used a panel of Chinese hamster X human somatic cell hybrids, each containing various portions of chromosome 21 as the only detectable human chromosome component, for regional mapping of cloned, chromosome 21-derived DNA sequences. Thirty unique and very low-repeat sequences were mapped to the short arm and three sections of the long arm. Three unique sequences map to the proximal part of the terminal band 21q22.3, and five to the distal part of this band. Some of these may represent parts of gene sequences that may be relevant to the pathogenesis of Down syndrome, as 21q22 is the area required to be present in triplicate for the full clinical picture.     

Chromosomal localization of the human homeo box-containing genes, EN1 and EN2

The human homologs of the mouse homeo box-containing genes, En-1 and En-2, which show homology to the Drosophila engrailed gene, have been isolated. The human EN1 gene was mapped to chromosome 2 by analysis of mouse-human somatic cell hybrids. The human EN2 gene was localized to chromosome 7, 7q32-7qter, by analysis of rodent-human somatic cell hybrids and cell lines carrying portions of chromosome 7.     

Characterization of pig-mink cell hybrids: assignment of the TK1 and UMPH2 genes to pig chromosome 12

By fusion of thymidine kinase-deficient mink cells with pig leukocytes, a new type of cell hybrid was produced. It was demonstrated that pig chromosomes segregate in pig-mink hybrids and that hybrid cells contain no cytologically visible rearrangements between the chromosomes of parental species, or chromosome fragmentation. With a set of subclones of two primary hybrid clones, the genes for thymidine kinase-1 (TK1) and uridine 5-monophosphate hydrolase-2 (UMPH2) were assigned to pig Chromosome (Chr) 12. A cell line with a single pig Chr 8 on the background of mink chromosomes was established. This clone could serve as a source of DNA for building a chromosome-specific library of pig Chr 8. The data obtained suggest that pig-mink cell hybrids can be used for mapping of pig chromosomes.     

Chromosomal and embryological analyses in sexual x apomictic hybrids ofPanicum maximum Jacq.

Summary Cytological analyses in series of crosses between 7 sexual pistillate and 8 apomictic staminate parents of speciesPanicum maximum (Gramineae) are reported. Although these 15 progenitors were tetraploid (2n = 32), 2 dihaploids (2n = 16), 45 hexaploids (2n = 48) and 5 octoploids (2n = 64) were observed among 333 progeny plants. The role of unreduced gametes as the originators of polyploidy is discussed in relation to the so-called elements of apomixis. The 2 dihaploids appeared to be sexual while the hexaploids and octoploids were all apomictic. At the tetraploid level sexual and apomictic hybrids segregated in a ratio close to 11. These results were then compared to those already obtained from studies on other tropical grasses and indicate a simple genetic determinism for gametophytic apomixis.