Localization of the mouse Mcf-2 (Dbl) protooncogene within a conserved linkage group on the mouse X chromosome

A mouse cDNA probe homologous to the human MCF2 transforming sequence has been identified and partially cloned, and is used here to localize the gene on the mouse X chromosome. The human gene has been physically mapped to within 60 kb of the gene for coagulation factor IX, within a large conserved linkage group between the mouse and human genomes which extends from HPRT to G6PD on the X chromosomes of both mammalian species. In situ hybridization of the mouse Mcf-2 probe onto mouse metaphase chromosomes indicates that this gene lies in the same region of the X chromosome as Cf-9, the mouse gene for coagulation factor IX. Moreover, segregation of species-specific genomic DNA polymorphisms for Mcf-2 and Cf-9 in a total of 203 individuals derived from two large interspecific mouse backcross populations (which are also segregating for 17 other X-linked molecular markers) demonstrates that the mouse genes are separated by only 0.5 +/- 0.5 cM. Despite this short distance we were able to order Mcf-2 and Cf-9 relative to one another and other genes in this region. The mouse gene order Hprt-Cf-9-Mcf-2-G6pd predicts a similar ordering of genes on the human X chromosome, a gene order which has only recently been demonstrated by physical mapping. Thus, the map location and linkage relationships of the Mcf-2 gene are similar in man and mouse, and this unique protooncogenic locus is part of a conserved linkage group on the mammalian X chromosome.     

Comparative mapping using somatic cell hybrids

Summary Comparative mapping, or ascertaining the gene linkage relationships between different species, is rapidly developing. This is possible because new techniques in chromosome identification and somatic cell hybridization, such as the generation of hybrids preferentially segregating chromosomes of any desired species including rodents, and the development of gene transfer techniques have yielded new information about the human and rodent gene maps. In addition, the discovery and characterization of mouse subspecies has generated new mouse sexual genetic linkage data. The following picture is emerging. Several X-linked genes in man are X-linked in all mammalian species tested. The linkage relationships of several tightly linked genes, less than 1 map unit apart, are also conserved in all mammalian species tested. Ape autosomal genes are assigned to ape chromosomes homologous to their human counterparts indicating extensive conservation in the 12 million years (MYR) of evolution from apes to man. Similarly, mouse and rat, 10 MYR apart in evolution, have several large autosomal synteny groups conserved. In comparing the mouse and human gene maps we find that human genes assigned to different arms of the same human chromosome are unlinked in the mouse; mouse genes large map distances (20 to 45 cM) apart are very likely to be unlinked in the human. However, several autosomal synteny groups 10 to 20 cM apart, including thePgd, Eno-1, Pgm-1 group on human chromosome arm lp, are conserved in mice and man. This suggests that homology mapping, the superimposition of one species gene map on the homologous conserved portion of another species genome may be possible, and that ancestral autosomal synteny groups should be detectable. Presented in the formal symposium on Somatic Cell Genetics at the 27th Annual Meeting of the Tissue Culture Association, Philadelphia, Pennsylvania, June 7–10, 1976.     

Mouse-human orthology relationships in an olfactory receptor gene cluster

The olfactory receptor (OR) subgenome harbors the largest known gene family in mammals, disposed in clusters on numerous chromosomes. One of the best characterized OR clusters, located at human chromosome 17p13.3, has previously been studied by us in human and in other primates, revealing a conserved set of 17 OR genes. Here, we report the identification of a syntenic OR cluster in the mouse and the partial DNA sequence of many of its OR genes. A probe for the mouse M5 gene, orthologous to one of the OR genes in the human cluster (OR17-25), was used to isolate six PAC clones, all mapping by in situ hybridization to mouse chromosome 11B3-11B5, a region of shared synteny with human chromosome 17p13.3. Thirteen mouse OR sequences amplified and sequenced from these PACs allowed us to construct a putative physical map of the OR gene cluster at the mouse Olfr1 locus. Several points of evidence, including a strong similarity in subfamily composition and at least four cases of gene orthology, suggest that the mouse Olfr1 and the human 17p13.3 clusters are orthologous. A detailed comparison of the OR sequences within the two clusters helps trace their independent evolutionary history in the two species. Two types of evolutionary scenarios are discerned: cases of "true orthologous genes" in which high sequence similarity suggests a shared conserved function, as opposed to instances in which orthologous genes may have undergone independent diversification in the realm of "free reign" repertoire expansion.     

Regional assignments of the zinc finger Y-linked gene (ZFY) and related sequences on human and mouse chromosomes

Recent chromosome walking experiments have identified a candidate gene (ZFY) for the testis-determining factor on the human Y chromosome (Page et al., 1987). We report here the regional assignments of the ZFY gene and related sequences in the human and the mouse. By in situ hybridization, we assigned ZFX and ZFY to human chromosome bands Xp21 and Yp11.3, respectively. Although the mouse harbors two Zfy genes, only one site at band A1 of its Y chromosome was significantly labeled. The mouse Zfx gene and the Zfa gene on chromosome 10 were assigned to bands XD and 10B5, respectively. These assignments of the ZFX gene in human and mouse add another marker to the conserved syntenic group for evaluating the evolutionary relationship of the human and mouse X chromosomes.     

Identification and mapping of swine cyclin-dependent kinase inhibitor CDKN2A and CDKN2B exon 2 sequences

We have isolated the swine homologs of human CDKN2A and CDKN2B exon 2 sequences. As in the human and mouse genomes, the exon 2 sequences of these two genes present a high level of sequence homology and are tightly linked. Using fluorescence in situ hybridization, we have mapped swine CDKN2A and CDKN2B to chromosome 1q25. This confirms the comparative mapping data among man, mouse, and swine, showing a conserved synteny among chromosome segments 9p21, 4C3-C6, and 1q25, respectively.     

Molecular cloning of mouse beta 2-glycoprotein I and mapping of the gene to chromosome 11.

beta 2-Glycoprotein I (beta 2 GPI), a plasma protein that binds to anionic phospholipids, is composed of five repeating units called a short consensus repeat (SCR), which is found mostly in the regulatory proteins of the complement system. Recently the human beta 2 GPI gene has been assigned to chromosome 17, not to chromosome 1 where most of the genes of the SCR-containing proteins are clustered. In this report, we have isolated a full-length cDNA clone of mouse beta 2 GPI and determined the chromosomal localization of the gene. The amino acid sequence deduced from the nucleotide sequence of mouse beta 2 GPI revealed 76.1% identity with that of human beta 2 GPI. A genetic mapping by in situ hybridization and linkage analysis using 50 backcross mice has shown that the mouse beta 2 GPI gene (designated B2gp1) is located on the terminal portion of the D region of chromosome 11, closely linked to Gfap, and is 18 cM distal to Acrb, extending a conserved linkage group between mouse chromosome 11 and human chromosome 17. On the basis of these results, the evolutionary relationships among the SCR-containing proteins are discussed.     

Localization of the photoreceptor gene ROM1 to human chromosome 11 and mouse chromosome 19: sublocalization to human 11q13 between PGA and PYGM.

Rom-1 is a retinal integral membrane protein that, together with the product of the human retinal degeneration slow gene (RDS), defines a photoreceptor-specific protein family. The gene for rom-1 (HGM symbol: ROM1) has been assigned to human chromosome 11 and mouse chromosome 19 by Southern blot analysis of somatic cell hybrid DNAs. ROM1 was regionally sublocalized to human 11p13-11q13 by using three mouse-human somatic cell hybrids; in situ hybridization refined the sublocalization to human 11q13. Analysis of somatic cell hybrids suggested that the most likely localization of ROM1 is in the approximately 2-cM interval between human PGA (human pepsinogen A) and PYGM (muscle glycogen phosphorylase). ROM1 appears to be a new member of a conserved syntenic group whose members include such genes as CD5, CD20, and OSBP (oxysterol-binding protein), on human chromosome 11 and mouse chromosome 19. Localization of the ROM1 gene will permit the examination of its linkage to hereditary retinopathies in man and mouse.     

Assignment of the gene for carboxypeptidase A to human chromosome 7q22→qter and to mouse chromosome 6

Summary A rat cDNA probe for preprocarboxypeptidase A was used to follow the segregation of the human gene for carboxypeptidase A (CPA) in 49 human x mouse somatic cell hybrids using Southern filter hybridization techniques. CPA was assigned to human chromosome 7q22qter. Similarly, the probe was used to follow the segregation of the mouse gene for carboxypeptidase A (Cpa) in 19 mouse x Chinese hamster somatic cell hybrids. Cpa was assigned to mouse chromosome 6. The gene for carboxypeptidase A forms part of a syntenic group that is conserved in man and mouse.Preliminary chromosomal assignments of carboxypeptidase A in man and mouse have been made in abstract (Honey et al. 1983a, b)     

Localization of the tumour protein, TP53, on porcine chromosome 12q12-q14

A human cDNA probe of the tumour protein p53 (TP53) was used to localize the homologous porcine gene by in situ hybridization. The gene was mapped to chromosome 12q12-q14. Together with already known mapping data, these results confirm the localization of an evolutionary conserved linkage group on porcine chromosome 12 which is localized in man on chromosome 17, in cattle on chromosome 19, and in mice on chromosome 11.     

A comparative linkage and physical map of bovine chromosome 24 with human chromosome 18

Polymorphic microsatellites have been developed in the vicinity of nine genes on bovine chromosome (BTA) 24, all orthologous to genes on human chromosome (HSA) 18. The microsatellites have been isolated from bacterial and yeast artificial chromosome clones containing the genes. A linkage map was developed including these polymorphic markers and four anonymous, published microsatellites. Yeast artificial chromosomes containing six of these genes have also been mapped using fluorescent in situ hybridization (FISH), thereby tying the linkage map together with the physical map of BTA24. Comparing gene location on HSA18 and BTA24 identifies four regions of conserved gene order, each containing at least two genes. These genes identify six regions of conserved order between human and mouse, two more than in the human-bovine comparison. The breakpoints between regions of conserved order for human-bovine are also breakpoints in the human-mouse comparison. The centromere identifies a fifth conserved region if the BTA24 centromere is orthologous with the HSA18 centromere. Received: 17 September 1998 / Accepted: 4 December 1998     

The human phosphoglycerate kinase multigene family. HLA-associated sequences and an X-linked locus containing a processed pseudogene and its functional counterpart

Several phosphoglycerate kinase genes were previously detected in the human genome by blot hybridization with a phosphoglycerate kinase cDNA probe. Using subcloned fragments of the cDNA we estimate the presence of four independent phosphoglycerate kinase genes. These genes have been mapped to both the human X chromosome (band q13) and chromosome 6 (p12-21.1) using a panel of human-rodent somatic cell hybrids and by chromosomal in situ hybridization. The genomic distribution of phosphoglycerate kinase sequences is conserved in man and mouse, not only for the X chromosome, but also for linkage to the respective major histocompatibility complexes. Molecular cloning of X-linked phosphoglycerate kinase sequences led to the identification of a novel intronless phosphoglycerate kinase pseudogene which is localized proximal to the active gene on the X chromosome.     

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.     

Physical mapping of the genes for three components of the mouse DNA replication complex: polymerase alpha to the X chromosome, primase p49 subunit to chromosome 10, and primase p58 subunit to chromosome 1

DNA polymerase alpha and primase are two key enzymatic components of the eukaryotic DNA replication complex. In situ hybridization of cloned cDNAs for mouse DNA polymerase alpha and for the two subunits of mouse primase has been utilized to physically map these genes in the mouse genome. The DNA polymerase alpha gene (Pola) was mapped to the mouse X chromosome in region C-D. The gene encoding the p58 subunit of primase (Prim2) was located to mouse chromosome 1 in region A5-B and the p49 subunit gene (Prim1) was found to be on mouse chromosome 10 in the distal part of band D that is close to the telomere. Current knowledge of mouse and human conserved chromosomal regions along with the findings presented here lead to predictions of where the genes for the DNA primase subunits may be found in the human genome: the p58 subunit gene may be on human chromosome 2 and the p49 subunit gene on human chromosome 12. The mapping of Pola to region C-D of the mouse X chromosome adds a new marker in a conserved region between the mouse X chromosome and region Xp21-22.1 of the human X chromosome.     

Conserved autosomal syntenic group on mouse (MMU) chromosome 15 and human (HSA) chromosome 22: assignment of a gene for arylsulfatase A to MMU 15 and regional mapping of DIA1, ARSA, and ACO2 on HSA 22

We have utilized a panel of Chinese hamster x mouse somatic cell hybrids segregating mouse chromosomes to assign a gene for arylsulfatase A (ARSA) to mouse chromosome 15. Considering our previous assignment of a gene for diaphorase-1 (DIA1) to the same mouse chromosome, we have evidence for another syntenic relationship that has been conserved, since the homologous loci for human ARSA and DIA1 are both located on human chromosome 22. Because MMU 15 and HSA 22 are quite dissimilar in size and banding patterns, we have attempted to identify the conserved portion by regional mapping of human DIA1 and ARSA using somatic cell hybrids segregating a human chromosome translocation t(15;22)(q14;q13.31). The results assign human DIA1 and ARSA to the distal sub-band of 22q13 (region 22q13.31 leads to qter). The locus for mitochondrial aconitase (ACO2) has been separated by the breakpoint from DIA1 and ARSA and is located more proximally.     

Regional localization of the fibronectin and gamma-crystallin genes to bovine chromosome 8

The genes for isocitrate dehydrogenase-1, fibronectin, and gamma-crystallin are syntenic in man, mouse, and cow. In an effort to assign this bovine syntenic group to a specific chromosome and to allow a cytological comparison of the conserved chromosomal region containing these genes in their respective species, we have localized the fibronectin and gamma-crystallin genes to bovine chromosome 8, region 1.1-1.4. This study incorporates the techniques of hybrid somatic cell analysis and in situ hybridization and the use of a Robertsonian-translocated marker chromosome from a related species for regional assignment of genes to a specific bovine chromosome. The regions on human chromosome 2q, mouse chromosome 1, and cow chromosome 8 that contain these genes are cytologically similar, perhaps representing evolutionary conservation at the cytogenetic level as well as at the gene level for this group of loci.     

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).     

Chromosomal mapping of the gene for the type II insulin-like growth factor receptor/cation-independent mannose 6-phosphate receptor in man and mouse

The gene for insulin-like growth factor II (IGF-II) receptor (IGF2R) that has recently been found, by DNA sequencing, to be identical to the cation-independent mannose 6-phosphate receptor (CIM6PR) has been mapped in the human and murine species. Cloned cDNAs for human and rat IGF-II receptors were used to probe Southern blots of somatic cell hybrid DNA and for in situ chromosomal hybridization. The genes are located in a region of other conserved syntenic genes on the long arm of human chromosome 6, region 6q25----q27, and mouse chromosome 17, region A-C. The CIM6PR/IGF2R locus in man is asyntenic with the genes encoding IGF-II (IGF2), the IGF-I receptor (IGF1R), and the cation-dependent mannose 6-phosphate receptor (CDM6PR).     

The alpha-A-crystallin and cystathionine beta-synthase genes are physically very closely linked in proximal mouse chromosome 17

Murine genes homologous to those contributing to the Down syndrome (DS) phenotype in man are currently of interest because of their potential for providing animal models for the study of specific DS symptoms. Most of the genes mapping to human chromosome 21q22, where the DS genes are concentrated, are related to sequences located on mouse chromosome 16. Others, however, are known to map to mouse chromosome 10, and two genes, cystathionine beta-synthase (Cbs) and alpha-A-crystallin (Crya-1), have been localized to the proximal portion of mouse chromosome 17. In this paper, we show that the two genes mapping to human chromosome 21q22 and mouse chromosome 17 are very tightly linked in mouse, being separated by at least 70 kb, but not more than 130 kb. The very close physical linkage of mouse Cbs and Crya-1, combined with data that localize homologs of the closely flanking markers H2k and Pim-1 to human chromosome 6, suggests that the human 21q22/mouse chromosome 17 conserved segment is of a very limited total physical size and is likely to contain a relatively small number of genes.     

Evolutionary breakpoints on human chromosome 21.

Segments of the long arm of human chromosome 21 are conserved, centromere to telomere, in mouse chromosomes 16, 17, and 10. There have been 28 genes identified in human chromosome 21 between TMPRSS2, whose orthologue is the most distal gene mapped to mouse chromosome 16, and PDXK, whose orthologue is the most proximal gene mapped to mouse chromosome 10. Only 6 of these 28 genes have been mapped in mouse, and all are located on chromosome 17. To better define the chromosome 17 segment and the 16 to 17 transition, we used a combination of mouse radiation hybrid panel mapping and physical mapping by mouse: human genomic sequence comparison. We have determined the mouse chromosomal location of an additional 12 genes, predicted the location of 7 more,and defined the endpoints of the mouse chromosome 17 region. The mouse chromosome 16/chromosome 17 evolutionary breakpoint is between human genes ZNF295 and UMODL1, showing there are seven genes in the chromosome 16 segment distal to Tmprss2. The chromosome 17/chromosome 10 breakpoint seems to have involved a duplication of the gene PDXK, which on chromosome 21 lies immediately distal to the KIAA0179 gene. These data suggest that there may be as few as 21 functional genes in the mouse chromosome 17 segment. This information is important for defining existing and constructing more complete mouse models of Down syndrome.