Regional mapping on human genes for phosphoglucomutase-1 on chromosome 1 and beta-glucuronidase on chromosome 7 using mouse x human hybrids.

Two independent mouse-human somatic cell hybrid clones contained different, de novo chromosome rearrangements involving the short arm of human chromosome 1. One hybrid clone contained a translocation between human chromosomes 1 and 7; the other clone contained a rearrangement product between human chromosomes 1 and 14. Analysis of these clones for expression of genes previously assigned to chromosome 7 and to the short arm of chromosome 1 provided evidence for localization of PGM--1 in segment 1p22.1 leads to 1p31.1, AK--2, ENO--1 and UMPK in region 1pter leads to 1p31.1, and GUS in region 7 pter leads to 7q22. The results have been used to examine the relationship between cytologic and genetic map distances on the short arm of chromosome 1.     

Gene mapping in the rat by mouse-rat somatic cell hybridization: synteny of the albumin and alpha-fetoprotein genes and assignment to chromosome 14

The methods of somatic cell genetics and molecular hybridization were applied to a panel of mouse X rat hepatocyte hybrids segregating rat chromosomes to assign the rat genes coding for two serum proteins, albumin and alpha-fetoprotein (Alb and Afp). The molecular hybridization of DNAs from different hybrids with cloned DNA probes showed that all the hybrid clones possessing the rat Alb gene and expressing it also retained the rat Afp locus, which is not expressed in these hybrids. So the Alb and Afp genes are syntenic in the rat, as in the mouse. Furthermore, the cytogenetic analysis allowed the assignment of these two loci to rat chromosome 14.     

Localization of human gene loci using spontaneous chromosome rearrangements in human-Chinese hamster somatic cell hybrids.

Analysis of human-Chinese hamster somatic cell hybrids with spontaneously derived chromosome structural changes has provided data for the regional and subregional localization of gene loci which have previously been assigned to human chromosomes 2, 12, and X. Correlation of the expression of human gene loci with the human chromosome complements present in somatic cell hybrids indicates that the cytoplasmic malate dehydrogenase (MDH1) locus is in the 2p23yields2pter region, and red cell acid phosphatase (AcP1) is at or adjacent to 2p23. The cytoplasmic isocitrate dehydrogenase (IDH1) locus is at or adjacent to 2q11, peptidase B (Pep B) is at or adjacent to 12q21, lactate dehydrogenase B (LDH B) is in the 12q21yiedls12pter region, glucose-6-phosphate dehydrogenase (G6PD) is in the Xq24yieldsXqter region, and the gene loci for phosphoglycerate kinase (PGK), alpha-galactosidase (alpha-gal), and hypoxanthine guanine phosphoribosyltransferase (GPRT) are in the Xp21yieldsXq24 region.     

Activity of both mouse and Chinese hamster ribosomal RNA genes in somatic cell hybrids

Nucleolus organizer regions (NOR) are actively expressed on both sets of parental chromosomes in mouse-Chines hamster hybrid cells retaining 85–95% of each parental complement. A hamster NOR, which is active in primary fetal hamster cells, but suppressed in the established AK412 line, is reactivated in these hybrids, demonstrating control of NOR expression.     

An informative panel of somatic cell hybrids for physical mapping on human chromosome 19q.

A panel of 22 somatic cell hybrids divides the q arm of human chromosome 19 into 22 ordered subregions. The panel was characterized with respect to 41 genetic markers. In most cases, a single fragment of chromosome 19 was present in each hybrid. In two cell lines the presence of multiple fragments of the chromosome was demonstrated by segregation of these fragments in subclones. On the basis of the results of marker analysis in this panel, the most likely order of the markers tested is MANB-D19S7-PEPD-D19S9-GPI-C/EBP-TGFB1++ +-(CYP2A,BCKDHA,CGM2,NCA)-PSG1-(D19S8, XRCC1)-(ATP1A3,D19S19)-(D19S37,APOC2)-C KM-ERCC2-ERCC1-(D19S116,D19S117)- (D19S118,D19S119, D19S63,p36.1,D19S112,D19S62,D19S51,D19S54, D19S55)-pW39-D19S6-(D19S50,TNNT1)-D19S2 2-(HRC,CGB,FTL,PRKCG)-qter. This gene order is generally consistent with published physical and genetic mapping orders, although some discrepancies exist. By means of a mapping function that relates the frequency of cosegregation of markers to the distance between them, estimates were made of the sizes, in megabases, of the 19q subregions. The relative physical distances between reference markers were compared with published genetic distances for 19q. Excellent correlation was observed, suggesting that the physical distances calculated by this method are predictive of genetic distances in this region of the genome and, therefore, are just as useful in estimating relative positions of markers.     

Normal X chromosome induced reversion in the direction of chromosome segregation in mouse-Chinese hamster somatic cell hybrids

The effect of a normal mouse X chromosome on the chromosome segregation of mouse-Chinese hamster somatic cell hybrids was determined by (i) producing hybrids between the mouse sarcoma line CMS4 and a microcell hybrid (mfe4) of the hamster line E36, containing a mouse X chromosome from a normal cell; (ii) isolating hybrids between CMS4 and a 6-thioguanine selected (X minus) mfe4 subpopulation; (iii) comparing the direction of segregation in the two sets of hybrids. It was found that the normal X chromosome, like the X chromosomes from two MCA-transformed sarcoma lines reported previously [9], has the ability to switch the chromosome segregation of mouse-Chinese hamster somatic cell hybrids. We conclude that the reversal in chromosome segregation is mediated by factors located on the X chromosome. We designate these genetic elements as segregation reversal genes or sr genes.     

Localization of genes on human chromosomes by studies of human-Chinese hamster somatic cell hybrids

Summary About 75 man-Chinese hamster hybrid clones were analysed for their human chromosome complement and simultaneously tested for human enzyme markers. Correlation of the presence of chromosomes and enzyme activity revealed assignments of the PGD linkage group to chromosome 1, ME₁, PGM₃ and IPO-B to 6, LDH-A to 11, LDH-B to 12 and IPO-A to 21.The assignment of PGM₃ puts the HL-A loci on chromosome 6. Segregation of the enzymes of the PGD linkage group was demonstrated in a clone which had retained a deleted chromosome 1. Subclones of this line indicate that the loci for PGD and PGM₁ are situated on the short arm or proximal part of the long arm of 1 and the locus for Pep-C on the long arm.

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Zusammenfassung Etwa 75 Hybrid-Zellklone Mensch/Chinesischer Hamster wurden in bezug auf den menschlichen Anteil ihres Chromosomensatzes analysiert und gleichzeitig auf menschliche Enzym-Marker untersucht. Die Korrelation zwischen Anwesenheit von Chromosomen und Enzym-Markern ließ die Folgerung zu, daß die PGD-Koppelungsgruppe auf Chromosom 1, ME₁, PGM₃ und IPO-B auf Nr. 6, LDH-A auf 11, LDH-B auf 12 und IPO-A auf Chromosom 21 gelegen ist.Die Lokalisation von PGM₃ läßt die Folgerung zu, daß auch die HL-A-loci auf Chromosom 6 lokalisiert sind. Aufspaltung der Enzyme der PGD-Koppelungsgruppe konnte an einem Klon dargestellt werden, der ein deletiertes Chromosom 1 enthielt. Die Subklone dieser Linie zeigen, daß die loci für PGD und PGM₁ auf dem kurzen Arm oder dem proximalen Teil des langen Arms von Chromosom Nr. 1 liegen, während der locus für Pep-C auf dem langen Arm gelegen ist.

     

Assignment of the genes for mouse type I procollagen to chromosome 16 using mouse fibroblast-Chinese hamster somatic cell hybrids

Somatic cell hybrids between mouse and Chinese hamster fibroblasts have been used to identify the chromosome responsible for the synthesis of both mouse type I procollagen subunit chains (MCOLA1 and MCOLA2). Thirty-one separate hybrid clones and subclones from ten separate hybridization events were isolated in hypoxanthine-aminopterin-thymidine (HAT) selection medium and were used for detailed gene-mapping studies. ELISA and "Western blotting" immunochemical analysis were used to detect the production of mouse type I procollagen in each hybrid clone. Mouse and Chinese hamster chromosomes were identified in each hybrid clone by trypsin-Giemsa banding of metaphase chromosome spreads and by isozyme analysis. We have found that mouse type I procollagen production segregates concordantly with mouse superoxide dismutase-1, previously mapped to mouse chromosome 16, and with the presence of mouse chromosome 16 karyotypically. Western blotting immunochemical analysis of the separated mouse procollagen chains produced by each hybrid line demonstrated that apparently the genes for both subunit chains are located on the same chromosome. These studies, therefore, assign the structural genes for mouse type I procollagen pro alpha 1 (MCOLA1) and pro alpha 2 (MCOLA2) chains to mouse chromosome 16.     

Characterization of beta-D-N-acetylhexosaminidase isoenzymes in man-Chinese hamster somatic cell hybrids.

A series of man-Chinese hamster hybrids were investigated with the use of an anti-Chinese hamster hexosaminidase serum, a specific anti-human hex A serum and an anti-human hex B serum. The expression of human hex A was found to be dependent on the presence of hex B. A heteropolymeric molecule is formed independently of hex B, which consists of Chinese hamster and specific hex A moieties. It has an electrophoretic mobility nearly identical to hex A. A relationship between the absence and presence of the heteropolymeric molecule, mannosephosphate isomerase (MPI), and pyruvate kinase (PK-3), assigned to chromosome 15, was established. With respect to the two locus subunit model, the gene coding for the alpha subunit, specific for hex A, has been localized on chromosome 15.     

Quantitative analysis of human chromosome segregation in man-mouse somatic cell hybrids.

The presumed random and independent process of human chromosome segregation in man-mouse somatic cell hybrids was studied. The results of chromosome analysis on 196 cells from 15 related hybrid strains have provided the first convincing evidence that segregation of human chromosomes can be nonindependent and often concordant. Different human chromosomes were not retained with equal frequency in these hybrid clones. Some were present in 80% of all the cells, whereas others appeared in less than 10% of the same cells. Linear regression analysis was used to test for correlation of the frequencies of all pair-wise combinations of human chromosomes present in these hybrid clones. Twenty-two of 136 possible correlations were statistically significant, indicating that concordant segregation of particular pairs of human chromosomes is a rather frequent occurrence.     

Selective linkage disruption in human-Chinese hamster cell hybrids: deletion mapping of the leuS, hexB, emtB, and chr genes on human chromosome 5.

Chinese hamster-human interspecific hybrid cells, which contain human chromosome 5 and express four genes linked on that chromosome, were subjected to selective conditions requiring them to retain one of the four linked genes, leuS (encoding leucyl-tRNA synthetase), but lose another, either emtB (encoding ribosomal protein S14) or chr. Cytogenetic and biochemical analyses of spontaneous segregants isolated by using these unique selective pressures have enabled us to determine the order and regional location of the leuS, hexB, emtB, and chr genes on human chromosome 5. These segregants arise primarily by terminal deletions of various portions of the long arm of chromosome 5. Our results indicate that the order of at least three of these genes is the same on human chromosome 5 and Chinese hamster chromosome 2. Thus, there appears to be extensive homology between Chinese hamster chromosome 2 and human chromosome 5, which represents an extreme example of the conservation of gene organization between very divergent mammalian species. In addition, these hybrids and selective conditions provide a very simple and quantitative means to assess the potency of various agents suspected of inducing gross chromosomal damage.     

Regional assignment of seven genes on chromosome 1 of man by use of man-Chinese hamster somatic cell hybrids. II. Results obtained after induction of breaks in chromosome 1 by X-irradiation.

The position of genes coding for PGD, PPH1, UGPP, GuK1, PGM1, Pep-C, and FH on human chromosome 1 was investigated by analysis of karyotype and enzyme phenotypes in man-Chinese hamster somatic cell hybrids carrying aberrations involving chromosome 1. Suitable hybrid cell lines were obtained by X-irradiation of hybrid cells carrying an intact chromosome 1 and by fusion of human cells from a clonal population carrying a translocation involving chromosome 1 with Chinese hamster cells. The latter human cell population had been isolated following X-irradiation of primary Lesch-Nyhan fibroblasts. In addition, products of de novo chromosome breakage in the investigated hybrid lines were utilized. By integrating the results of these analyses with earlier findings in our laboratory, the following positions of genes are deduced: PGD and PPH1 in 1p36 leads to 1p34; PGM1 in 1p32; UGPP in 1q21 leads to 1q23; GuK1 in 1q31 leads to 1q42; Pep-C in 1q42; and FH in 1qter leads to 1q42.     

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.     

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.