Assignment of three rat integrin genes to Chromosome 19 (ITGB1), Chromosome 3 (ITGA4), and Chromosome 7 (ITGA5)

By means of somatic cell, hybrids segregating rat chromosomes, we determined the chromosome localization of three rat 1 family integrin genes. ITGB1 was assigned to Chromosome (Chr) 19, ITGA4 to Chr 3, and ITGA5 to Chr 7. These chromosome assignments reveal or confirm homology between two pairs of rat and human chromosomes (rat Chr 3-human Chr 2; rat Chr 7-human Chr 12).     

Chromosomal assignment of four rat genes coding for the spermatid-specific proteins proacrosin (ACR), transition proteins 1 (TNP1) and 2 (TNP2), and protamine 1 (PRM1)

The genes for proacrosin, protamines, and transition proteins are exclusively expressed in haploid spermatogenic cells. From the analysis of mouse x rat cell hybrids which segregate rat chromosomes, the rat gene for proacrosin (ACR) was assigned to chromosome 7, that for transition protein 1 (TNP1) to chromosome 9, and the genes for transition protein 2 (TNP2) and protamine 1 (PRM1) to chromosome 10.     

Regional localization of three convertases, PC1 (Nec-1), PC2 (Nec-2), and furin (Fur), on mouse chromosomes.

The genes for three convertases, PC1 (Nec-1), PC2 (Nec-2), and furin (Fur), have been regionally localized on chromosomes 13, 2, and 7, respectively, by interspecific backcross analysis. These results refine previous localizations by in situ hybridization as well as confirm and extend known regions of homology between mouse and human chromosomes.     

Chromosomal assignment of retinoic acid receptor (RAR) genes in the human, mouse, and rat genomes.

The human genes encoding the alpha and beta forms of the retinoic acid receptor are known to be located on chromosomes 17 (band q21.1:RARA) and 3 (band p24:RARB). By in situ hybridization, we have now localized the gene for retinoic acid receptor gamma, RARG, on chromosome 12, band q13. We also mapped the three retinoic acid receptor genes in the mouse, by in situ hybridization, on chromosomes 11, band D (Rar-a); 14, band A (Rar-b); and 15, band F (Rar-g), respectively, and in the rat, using a panel of somatic cell hybrids that segregate rat chromosomes, on chromosomes 10 (RARA), 15 (RARB), and 7 (RARG), respectively. These assignments reveal a retention of tight linkage between RAR and HOX gene clusters. They also establish or confirm and extend the following homologies: (i) between human chromosome 17, mouse chromosome 11, and rat chromosome 10 (RARA); (ii) between human chromosome 3, mouse chromosome 14, and rat chromosome 15 (RARB); and (iii) between human chromosome 12, mouse chromosome 15, and rat chromosome 7 (RARG).     

Assignment of the rat genes coding for medium-chain acyl-CoA dehydrogenase, isovaleryl-CoA dehydrogenase, and the beta subunit of propionyl-CoA carboxylase to chromosomes 2, 3, and 8, respectively

From the analysis of mouse x rat cell hybrids which segregate rat chromosomes, the rat genes coding for the enzymes medium-chain acyl-CoA dehydrogenase, isovaleryl-CoA dehydrogenase, and the beta-subunit of propionyl-CoA carboxylase have been assigned to chromosomes 2, 3, and 8, respectively.     

The gene map of the Norway rat (Rattus norvegicus) and comparative mapping with mouse and man

The current status of the rat gene map is presented. Mapping information is now available for a total of 214 loci and the number of mapped genes is increasing steadily. The corresponding number of loci quoted at HGM10 was 128. Genes have been assigned to 20 of the 22 chromosomes in the rat. Some aspects of comparative mapping with mouse and man are also discussed. It was found that there is a good correlation between the morphological homologies detectable in rat and mouse chromosomes, on the one hand, and homology at the gene level on the other. For 10 rat synteny groups all the genes so far mapped are syntenic also in the mouse. For the remaining rat synteny groups it appears that the majority of the genes will be syntenic on specific (homologous) mouse chromosomes, with only a few genes dispersed to other members of the mouse karyotype. Furthermore, the data indicate that mouse chromosome 1 genetically corresponds to two rat chromosomes, viz., 9 and 13, equalizing the difference in chromosome number between the two species. Further mappings will show whether the genetic homology will prove to be as extensive as these preliminary results indicate. As might be expected from evolutionary considerations, rat synteny groups are much more dispersed in the human genome. It is clear, however, that many groups of genes have remained syntenic during the period since man and rat shared a common ancestor. One further point was noted. In two cases groups of genes were syntenic in the mouse but dispersed to two chromosomes in rat and man, whereas in a third case a group of genes was syntenic in the rat but dispersed to two chromosomes in mouse and man. This finding argues in favor of the notion that the original gene groups were on separate ancestral chromosomes, which have fused in one rodent species but remained separate in the other and in man.     

Regional localization of three convertases, PC1 (Nec-1), PC2 (Nec-2), and furin (Fur), on mouse chromosomes

The genes for three convertases, PC1 (Nec-1), PC2 (Nec-2), and furin (Fur), have been regionally localized on chromosomes 13, 2, and 7, respectively, by interspecific backcross analysis. These results refine previous localizations by in situ hybridization as well as confirm and extend known regions of homology between mouse and human chromosomes.     

Assignment of three rat genes coding for plasma proteins, transferrin, third component of complement, and beta-fibrinogen to rat chromosomes 8, 9, and 2

The assignment of three rat genes coding for plasma proteins has been deduced from the analysis of rat x mouse cell hybrids. The transferrin and the third component of complement genes were localized on rat chromosomes 8 and 9 respectively, and the beta-fibrinogen gene on chromosome 2.     

Chromosomal assignments of 17 structural genes and 11 related DNA fragments in rats (Rattus norvegicus) by Southern blot analysis of rat x mouse somatic cell hybrid clones.

DNA from 18 rat x mouse somatic cell hybrid clones, which segregated individual rat chromosomes, was analyzed by Southern blot for chromosomal gene assignments. Through the use of 17 DNA probes cloned from 7 rat genes, A2M, ATP1A1, ATP1A2, ATP1A3, B2M, GSTP, and SMST; 5 mouse genes, Ncam, Ngfg, Pim-1, Tcp-1, and Trp53; and 5 human genes, MBP, MYB, NEFM, SCN2A, and TCRGC1, 17 structural genes including 15 newly assigned genes and 11 related DNA fragments were assigned to particular rat chromosomes. Syntenic conservation of the genes among rats, mice, and humans is discussed.     

Location of rRNA genes in three inbred strains of rat and suppression of rat rRNA activity in rat-human somatic cell hybrids

Nucleolus organizer regions (NORs) of rat chromosomes were stained by the Ag-AS method. The Ag-NORs were found on chromosomes 3, 11 and 12 in the ACI, Wistar Brown and Wistar Lewis inbred strains of rat. The size of the Ag-NOR on each pair of chromosomes varied from strain to strain. Rat-human somatic hybrid cells that retained human and lost some of the rat chromosomes had no Ag-NOR on rat chromosomes 3, 11 or 12. Since NORs can be Ag-stained only if their 18 + 28S rRNA genes are active, the activity of the rat rRNA genes must have been suppressed in the hybrid cells.     

Chromosomal localization of human and rat A alpha, B beta, and gamma fibrinogen genes by in situ hybridization

In situ hybridization of radiolabeled fibrinogen cDNAs to human and rat metaphase chromosomes has shown that the genes encoding the A alpha, B beta, and gamma fibrinogen subunits are syntenic in both species. Our data localize the human fibrinogen gene cluster to band q31 on chromosome 4, thereby confirming and extending previous map assignments of these genes in man. We have also assigned these genes to the q31----q34 region of rat chromosome 2. This is the first map assignment of these genes in the rat and also the first report to clearly establish linkage of the B beta subunit gene to the A alpha and gamma genes in this species.     

Chromosomal assignments of genes for rat glutathione S-transferase Ya (GSTA1) and Yc subunits (GSTA2).

Chromosomal assignments of genes for rat glutathione S-transferase Ya (GSTA1) and Yc subunits (GSTA2) were performed by Southern blot analyses of somatic cell hybrid DNAs.GSTA1 and GSTA2 were assigned to rat chromosomes 8 and 9, respectively.     

Mapping of the genes for rat endothelin receptor type A (ETAR) and type B (ETBR) to chromosomes 19 and 15 respectively

Chromosomal assignments of the genes for rat endothelin receptor type A (ET_AR) and type B (ET_BR) were performed by analysing somatic cell hybrid DNAs with the polymerase chain reaction (PCR) using primers specific for rat ET_AR and ET_BR genes. The genes for ET_AR and ET_BR were assigned to rat chromosomes 19 and 15 respectively.     

Rat Chromosome 1: Regional localization of seven genes (Slc9a3, Srd5a1, Esr, Tcp1, Grik5, Tnnt3, Jak2) and anchoring of the genetic linkage map to the cytogenetic map

Seven genes were regionally localized on rat Chromosome (Chr) 1, from 1p11 to 1q42, and two of these genes were also included in a linkage map. This mapping work integrates the genetic linkage map and the cytogenetic map, and allows us to orient the linkage map with respect to the centromere, and to deduce the approximate position of the centromere in the linkage map. These mapping data also indicate that the Slc9a3 gene, encoding the Na⁺/H⁺ exchanger 3, is an unlikely candidate for the blood pressure loci assigned to rat Chr 1. These new localizations expand comparative mapping between rat Chr 1 and mouse or human chromosomes. Received: 21 March 1997 / Accepted: 3 May 1997     

Two human genes encoding zinc finger proteins,ZNF12 (KOX 3) and ZNF 26 (KOX 20), map to chromosomes 7p22-p21 and 12q24.33, respectively

Summary Two members of the human zinc finger Krüppel family, ZNF 12 (KOX 3) and ZNF 26 (KOX 20), have been localized by somatic cell hybrid analysis and in situ chromosomal hybridization. The presence of individual human zinc finger genes in mouse-human hybrid DNAs was correlated with the presence of specific human chromosomes or regions of chromosomes in the corresponding cell hybrids. Analysis of such mouse-human hybrid DNAs allowed the assignment of the ZNF 12 (KOX 3) gene to chromosome region 7p. The ZNF 26 (KOX 20) gene segregated with chromosome region 12q13-qter. The zinc finger genes ZNF 12 (KOX 3) and ZNF 26 (KOX 20) were localized by in situ chromosomal hybridization to human chromosome regions 7p22-21 and 12q24.33, respectively. These genes and the previously mapped ZNF 24 (KOX 17) and ZNF 29 (KOX 26) genes, are found near fragile sites.     

Localization of genes on fractionated rat chromosomes by molecular hybridization

Chromosomes derived from rat kidney cells were separated in specially designed sedimentation chambers by velocity sedimentation at 30 g. The DNA of the chromosomal fractions was used in molecular hybridization experiments to localize single-copy genes on the fractionated rat chromosomes. By cross-hybridization with a mouse immunoglobulin light chain kappa c-DNA probe, the rat immunoglobulin genes were detected only on the DNA of chromosomal fractions highly enriched for chromosomes 3, 4 and 5. The rat albumin gene was detected on fractions greatly enriched for chromosomes 11, 13 and 14. The described method allows the localization of structural genes or introduced DNA sequences on the chromosomal level especially in those cell systems in which no suitable somatic cell hybrids are available.     

A glutaminase (gis) gene maps to mouse chromosome 1, rat chromosome 9, and human chromosome 2

A rat cDNA clone encoding a portion of phosphate-activated glutaminase was used to identify DNA restriction fragment length polymorphisms (RFLPs) in sets of somatic cell hybrids and between wild-derived and inbred strains of mice. Segregation of rat and mouse chromosomes among somatic cell hybrids indicated assignment to rat chromosome 9 and mouse chromosome 1. Analysis of chromosome 1 alleles for several genes in an interspecific cross between Mus spretus and C3H/HeJ-gld/gld mice indicates that glutaminase can be positioned within 5.5 +/- 2.0 cM proximal to Ctla-4. Similarly, human-hamster somatic cell hybrids were examined for RFLPs, and four human EcoRI restriction fragments were found to hybridize with the rat glutaminase probe. Two of these restriction fragments cosegregated and mapped to human chromosome 2 in a region that is syntenic with mouse chromosome 1 and rat chromosome 9.