The mouse Rsk3 gene maps to the Leh66 elements carrying the t-complex responder Tcr

A variant form of mouse Chromosome (Chr) 17, the t-haplotype, contains several loci responsible for transmission ratio distortion in males. Sperm carrying the responder locus (Tcr) have a high probability of fertilizing eggs at the expense of wild-type sperm, provided that distorter loci (Tcd-1 to Tcd-5) are expressed during spermatogenesis. Tcr has been mapped to the Leh66b region within a maximum of 155 kb. In the search for genes in the genomic region Leh66EI, we have identified the mouse homolog of human ribosome S6 kinase 3 (RSK3) on cosmid DNA. The complete mouse Rsk3 gene is encoded in the region Leh66a of t-haplotypes and Leh66EI of the wild-type chromosome. It consists of at least 13 exons spanning over more than 120 kb. Rsk3 is expressed in embryos and in several adult organs including testis. Cosmids covering 100 kb of the Leh66b region or 120 kb of the Leh66a region were isolated. Rsk3 covers about 65 kb of the Leh66b region and appears to be incomplete at its 5′-end. A correlation of the physical map provided here with the genetic mapping of Tcr reported previously suggests that Tcr is most likely encoded within a fragment of 30 kb upstream or 20 kb downstream of Rsk3. These data will facilitate the isolation of Tcr, a prerequisite for understanding transmission ratio distortion in mouse. Received: 21 January 1999 / Accepted: 16 April 1999     

cDNA Cloning and Gene Mapping of Human Homologs forSchizosaccharomyces pombe rad17, rad1,andhus1and Cloning of Homologs from Mouse,Caenorhabditis elegans,andDrosophila melanogaster

Mutations in DNA repair/cell cycle checkpoint genes can lead to the development of cancer. The cloning of human homologs of yeast DNA repair/cell cycle checkpoint genes should yield candidates for human tumor suppressor genes as well as identifying potential targets for cancer therapy. TheSchizosaccharomyces pombegenesrad17, rad1,andhus1have been identified as playing roles in DNA repair and cell cycle checkpoint control pathways. We have cloned the cDNA for the human homolog ofS. pombe rad17,RAD17, which localizes to chromosomal location 5q13 by fluorescencein situhybridization and radiation hybrid mapping; the cDNA for the human homolog ofS. pombe rad1,RAD1, which maps to 5p14–p13.2; and the cDNA for the human homolog ofS. pombe hus1,HUS1, which maps to 7p13–p12. The human gene loci have previously been identified as regions containing tumor suppressor genes. In addition, we report the cloning of the cDNAs for genes related toS. pombe rad17, rad9, rad1,andhus1from mouse,Caenorhabditis elegans,andDrosophila melanogaster.These includeRad17andRad9fromD. melanogaster,hpr-17 and hpr-1 fromC. elegans,and RAD1 and HUS1 from mouse. The identification of homologs of theS. pomberad checkpoint genes from mammals, arthropods, and nematodes indicates that this cell cycle checkpoint pathway is conserved throughout eukaryotes.     

Homologs of genes and anonymous loci on human Chromosome 13 map to mouse Chromosomes 8 and 14

To enhance the comparative map for human Chromosome (Chr) 13, we identified clones for human genes and anonymous loci that cross-hybridized with their mouse homologs and then used linkage crosses for mapping. Of the clones for four genes and twelve anonymous loci tested, cross-hybridization was found for six, COL4A1, COL4A2, D13S26, D13S35, F10, and PCCA. Strong evidence for homology was found for COL4A1, COL4A2, D13S26, D13S35, and F10, but only circumstantial homology evidence was obtained for PCCA. To genetically map these mouse homologs (Cf10, Col4a1, Col4a2, D14H13S26, D8H13S35, and Pcca-rs), we used interspecific and intersubspecific mapping panels. D14H13S26 and Pcca-rs were located on the distal portion of mouse Chr 14 extending by 30 cM the conserved linkage between human Chr 13 and mouse Chr 14, assuming that Pcca-rs is the mouse homolog of PCCA. By contrast, Cf10, Col4a1, Col4a2, and D8H13S35 mapped near the centromere of mouse Chr 8, defining a new conserved linkage. Finally, we identified either a closely linked sequence related to Col4a2, or a recombination hot-spot between Col4a1 and Col4a2 that has been conserved in humans and mice.     

Comparative mapping of mouse Chromosome 4 and human Chromosome 9: Lv,Orm, and Hxb are closely linked on mouse Chromosome 4

The genes for orosomucoid (ORM-1 and ORM-2), delta-aminolevulinate dehydratase (ALAD), and hexabrachion or tenascin (HXB) all map to the q31-qter region of human Chromosome (Chr) 9. The mouse homolog of each of these genes has been mapped to Chr 4, but hexabrachion has not previously been mapped by linkage analysis. We have now ordered Orm-1, Lv (the mouse homolog of ALAD), and Hxb in an interspecific backcross panel, by use of tyrosinase related protein-1, Tyrp-1, whose human homolog maps to 9p13-pter (Abbott et al., Genomics 1991) as a reference locus. No recombinants were identified in 124 animals between Lv and Orm-1. Hxb was found to be 1.6 cM distal to Lv and Orm-1, and 4.8 cM proximal to Tyrp-1, or b. These data therefore contribute to our knowledge of the conserved synteny between HSA 9q and MMU 4.     

Characterization of the murine polycystic kidney disease (Pkd2) gene

Autosomal dominant polycystic kidney disease (ADPKD) is one of the most frequent genetically transmitted disorders among Europeans with an attributed frequency of 0.1%. The two most common genetic determinants for ADPKD are the PKD1 and PKD2 genes. In this study we report the genomic structure and pattern of expression of the Pkd2 gene, the murine homolog of the human PKD2 gene. Pkd2 is localized on mouse Chromosome (Chr) 5 proximal to anchor marker D5Mit175, spans at least 35 kb of the mouse genome, and consists of 15 exons. Its translation product consists of 966 amino acids, and the peptide shows a 95% homology to human polycystin2. Functional domains are particularly well conserved in the mouse homolog. The expression of mouse polycystin2 in the developing embryo at day 12.5 post conception is localized in mesenchymally derived structures. In the adult mouse, the protein is mostly expressed in kidney, which suggests its functional relevance for this organ. Received: 13 March 1998 / Accepted: 11 May 1998     

Colinearity of novel genes in the class II regions of the MHC in mouse and human

To examine the degree of conservation of gene organization in and around the class II regions of the major histocompatibility complexes of mouse and human, we have established the positions of sequences homologous to five human non-class II genes (RING1-5) in mouse, and the positions of sequences homologous to three mouse non-class II genes (KE3-5) in human. The resulting comparative map reveals that the organization of genes in the entire proximal region of the MHCs of mouse and human is remarkably conserved, apart from the H-2K gene pair in mouse, which can be accounted for by a 60 kilobase (kb) insertion. The characterization of the novel human gene RING5 is also presented. This gene, which is widely expressed, maps 85 kb proximal to the DPB2 gene. Partial nucleotide sequencing of a RING5 cDNA clone reveals that it is the human homolog of the mouse KE4 gene.The nucleotide sequence data reported in this paper have been submitted to the GenBank nucleotide sequence database and have been assigned the accession number M58660.     

Genes for the CPE Receptor (CPETR1) and the Human Homolog of RVP1 (CPETR2) Are Localized within the Williams–Beuren Syndrome Deletion

Williams–Beuren syndrome (WBS) is a neurodevelopmental disorder affecting multiple systems. Haploinsufficiency of genes deleted in chromosomal region 7q11.23 is the likely cause for this syndrome. We now report the localization of the genes for the CPE-R (Clostridium perfringensenterotoxin receptor,CPETR1) and the human homolog of RVP1 (rat ventral prostate 1 protein,CPETR2), both previously mapped to 7q11, to the WBS critical region. A single nucleotide polymorphism (SNP) present inCPETR1has been identified and was used to determine parental origin of the deleted allele in five informative families. The mouse homologsCpetr1andCpetr2were identified and mapped to the conserved syntenic region on mouse chromosome 5. Northern blot analysis ofCPETR1demonstrates tissue specificity, with expression in kidney, lung, thyroid, and gastrointestinal tissues. In mouse,Cpetr1is expressed in the early embryo, appears to be developmentally upregulated during gestation, and is present in adult tissues. Our results suggest a role for CPE-R in internal organ development and function during pre- and postnatal life.     

Chromosomal Localization and Genomic Organization of Genes Encoding Guanylyl Cyclase Receptors Expressed in Olfactory Sensory Neurons and Retina

We recently cloned three membrane guanylyl cyclases, designated GC-D, GC-E, and GC-F, from rat olfactory tissue and eye. Amino acid sequence homology suggests that they may compose a new gene subfamily of guanylyl cyclase receptors specifically expressed in sensory tissues. Their chromosomal localization was determined by mouse interspecific backcross analysis. The GC-D, GC-E, and GC-F genes (Gucy2d, Gucy2e,andGucy2f) are dispersed through the mouse genome in that they map to chromosomes 7, 11, and X, respectively. Close proximity of the mouse GC-D gene toOmp(olfactory marker protein) andHbb(hemoglobin β-chain complex) suggests that the human homolog gene maps to 11p15.4 or 11q13.4–q14.1. The human GC-F gene was localized to the long arm of chromosome Xq22 by fluorescencein situhybridization. The genomic organization of the mouse GC-E gene was determined and compared to other guanylyl cyclase genes. The mouse GC-D, GC-E, and GC-F genomic clones contain identical exon–intron boundaries within their extracellular and cytoplasmic domains, demonstrating the conservation of the gene structures. With respect to human genetic diseases, GC-E mapped to mouse chromosome 11 within a syntenic region on human chromosome 17p13 that has been linked with loci for autosomal dominant retinitis pigmentosa and Leber congenital amaurosis. No apparent disease loci have been yet linked to the locations of the GC-D or GC-F genes.     

Rapid evolution of human pseudoautosomal genes and their mouse homologs

Comparative studies of genes in the pseudoautosomal region (PAR) of human and mouse sex chromosomes have thus far been very limited. The only comparisons that can presently be made indicate that the PARs of humans and mice are not identical in terms of gene content. Here we describe additional comparative studies of human pseudoautosomal genes and their mouse homologs. Using a somatic cell hybrid mapping panel, we have assigned the mouse homolog of the human pseudoautosomal interleukin 3 receptor alpha subunit (IL3RA) gene to mouse Chromosome (Chr) 14. Attempts to clone the mouse homolog of the human pseudoautosomal adenine nucleotide translocase-3 (ANT3) gene resulted in the isolation of the murine homologs of the human ANT1 and ANT2 genes. The mouse Ant1 and Ant2 genes are very similar in sequence to their human homologs, and we have mapped them to mouse Chromosomes (Chrs) (8 and X respectively) that exhibit conserved synteny with the chromosomes on which the human genes are located. In contrast, the homolog of ANT3 appears to be either very divergent or absent from the mouse genome. Southern blot analysis of DNA from a variety of mammalian species shows restricted conservation of human pseudoautosomal genes, a trend that also applies to the two cloned mouse homologs of these genes and to neighboring human genes in distal Xp22.3. Our observations combined with those of other workers lead us to propose a model for the evolution of the PAR that includes both rapid sequence evolution and the incremental reduction in size of the region during mammalian evolution. Received: 4 May 1995 / Accepted: 21 August 1995     

Refined Mapping of the Usher Syndrome Type III Locus on Chromosome 3, Exclusion of Candidate Genes, and Identification of the Putative Mouse Homologous Region

A locus for Usher syndrome type III (USH3;MIM No. 276902) was recently assigned to a 5-cM region on chromosome 3q. We constructed a yeast artificial chromosome contig that allowed us to position novel polymorphisms in the region. These were typed in a total of 32 pedigrees from a geographically isolated Finnish founder population in which a putative single ancestralUSH3mutation segregates. A multipoint linkage analysis assignedUSH3to a 4-cM region betweenD3S1555and a novel markerD3S3625.By analysis of linkage disequilibrium and historical recombinations in 77USH3chromosomes, the location of the Finnish USH3 mutation could be narrowed to an approximately 1-cM interval between the markersD3S1299andD3S3625.A gene for profilin-2 (PFN2) was mapped in the vicinity and excluded as a candidate for USH3 by sequencing. The putative mouse homolog ofPFN2was mapped to mouse chromosome 3, thus suggesting a localization for the mouse homolog ofUSH3.     

Lack of Pwcr1/MBII-85 snoRNA is critical for neonatal lethality in Prader–Willi syndrome mouse models

Prader–Willi syndrome (PWS) is a neurobehavioral disorder caused by the lack of paternal expression of imprinted genes in the human chromosome region 15q11–13. Recent studies of rare human translocation patients narrowed the PWS critical genes to a 121-kb region containing PWCR1/HBII-85 and HBII-438 snoRNA genes. The existing mouse models of PWS that lack the expression of multiple genes, including Snrpn, Ube3a, and many intronic snoRNA genes, are characterized by 80%–100% neonatal lethality. To define the candidate region for PWS-like phenotypes in mice, we analyzed the expression of several genetic elements in mice carrying the large radiation-induced p^30PUb deletion that includes the p locus. Mice having inherited this deletion from either parent develop normally into adulthood. By Northern blot and RT-PCR assays of brain tissue, we found that Pwcr1/MBII-85 snoRNAs are expressed normally, while MBII-52 snoRNAs are not expressed when the deletion is paternally inherited. Mapping of the distal deletion breakpoint indicated that the p^30PUb deletion includes the entire MBII-52 snoRNA gene cluster and three previously unmapped EST sequences. The lack of expression of these elements in mice with a paternal p^30PUb deletion indicates that they are not critical for the neonatal lethality observed in PWS mouse models. In addition, we identified MBII-436, the mouse homolog of the HBII-436 snoRNA, confirmed its imprinting status, and mapped it outside of the p^30PUb deletion. Taking together all available data, we conclude that the lack of Pwcr1/MBII-85 snoRNA expression is the most likely cause for the neonatal lethality in PWS model mice.     

Human and murine PTX1/Ptx1 gene maps to the region for Treacher Collins Syndrome

Ptx1 belongs to an expanding family of bicoid-related vertebrate homeobox genes. These genes, like their Drosophila homolog, seem to play a role in the development of anterior structures and, in particular, the brain and facies. We report the chromosomal localization of mouse Ptx1, and the cloning, sequencing, and chromosomal localization of the human homolog PTX1. The putative encoded proteins share 100% homology in the homeodomain and are 88% and 97% conserved in the N- and C-termini respectively. Intron/exon boundaries are also conserved. Murine Ptx1 was localized, by interspecific backcrossing, to Chr 13 within 2.6 cM of Caml. The gene resides centrally on Chromosome (Chr) 13 in a region syntenic with human Chr 5q. Subsequent analysis by fluorescent in situ hybridization places the human gene, PTX1, on 5q31, a region associated with Treacher Collins Franceschetti Syndrome. Taken together with the craniofacial expression pattern of Ptx1 during early development, the localization of the gene in this chromosomal area is consistent with an involvement in Treacher Collins Franceschetti Syndrome. Received: 3 May 1997 / Accepted: 1 July 1997     

New gene in the homologous human 11q13–q14 and mouse 7F chromosomal regions

Alterations in the chromosomal region 11q13–11q14 are involved in several pathologies in which most of the key genes remain to be identified. In an effort to isolate as many candidates as possible, we are cloning genes from this region. We report here the mapping for a new sequence from 11q13.5–11q14. This sequence, designated D11S833E, putatively encodes a new gene, provisionally named GARP. We cloned its homologous sequence in the mouse and located it on Chromosome (Chr) 7, region F. The human and mouse genes belong to a conserved group of synteny. This, together with the similar conservation of the FGF and TYR genes, indicates that the human 11q13–q14 and mouse 7E-7F regions share homology.     

Murine Stim1 maps to distal Chromosome 7 and is not imprinted

STIM1 (GOK) maps to a region of human Chromosome (Chr) 11p15.5 that is implicated in several embryonal tumors, and some evidence indicates that STIM1 may have a growth suppressor role in rhabdomyosarcoma. In this study we have mapped the murine homolog, Stim1, to the same position as Hbb on distal mouse Chr 7. This region is separated by 20 cM from the region of distal Chr 7 that contains Igf2, H19, and other imprinted genes. Using strain-specific polymorphisms, we have shown that Stim1 is expressed from both parental alleles in fetal and neonatal mouse tissues. Similar analyses of human Wilms' tumor and normal kidney tissues demonstrated biallelic expression of STIM1 in the majority of samples. These data demonstrate that Stim1 expression is not regulated by genomic imprinting in either mouse or human tissues. Thus, if STIM1 is a tumor suppressor at 11p15.5, loss of expression is not due to imprinting effects. Received: 23 January 1998 / Accepted: 10 April 1998     

Retrotransposed genes such as Frat3 in the mouse Chromosome 7C Prader-Willi syndrome region acquire the imprinted status of their insertion site

Prader-Willi syndrome (PWS) results from loss of function of a 1.0- to 1.5-Mb domain of imprinted, paternally expressed genes in human Chromosome (Chr) 15q11-q13. The loss of imprinted gene expression in the homologous region in mouse Chr 7C leads to a similar neonatal PWS phenotype. Several protein-coding genes in the human PWS region are intronless, possibly arising by retrotransposition. Here we present evidence for continued acquisition of genes by the mouse PWS region during evolution. Bioinformatic analyses identified a BAC containing four genes, Mkrn3, Magel2, Ndn, Frat3, and the Atp5l-ps1 pseudogene, the latter two genes derived from recent L1-mediated retrotransposition. Analyses of eight overlapping BACs indicate that these genes are clustered within 120 kb in two inbred strains, in the order tel–Atp5l-ps1–Frat3–Mkrn3–Magel2–Ndn–cen. Imprinting analyses show that Frat3 is differentially methylated and expressed solely from the paternal allele in a transgenic mouse model of Angelman syndrome, with no expression from the maternal allele in a mouse model of PWS. Loss of Frat3 expression may, therefore, contribute to the phenotype of mouse models of PWS. The identification of five intronless genes in a small genomic interval suggests that this region is prone to retroposition in germ cells or their zygotic and embryonic cell precursors, and that it allows the subsequent functional expression of these foreign sequences. The recent evolutionary acquisition of genes that adopt the same imprint as older, flanking genes indicates that the newly acquired genes become `innocent bystanders' of a primary epigenetic signal causing imprinting in the PWS domain. Received: 22 May, 2001 / Accepted: 16 July 2001     

High-resolution mapping of mouse Chromosome 8 identifies an evolutionary chromosomal breakpoint

The central region of mouse Chromosome (Chr) 8, containing the myodystrophy (myd) locus, is syntenic with human Chr 4q28-qter. The human neuromuscular disorder facioscapulohumeral muscular dystrophy (FSHD) maps to Chr 4q35, and myd has been proposed as a mouse homolog of FSHD. We have employed a comparative mapping approach to investigate this relationship further by extending the mouse genetic map of this region. We have ordered 12 genes in a single cross, 8 of which have human homologs on 4q28-qter. The results confirm a general relationship between the most distal genes on human 4q and the most proximal genes in the mouse 8 syntenic region. Despite chromosomal rearrangements of syntenic groups in this region, conservation of gene order is maintained between the group of genes in the human telomeric region of 4q35 and MMU8. Furthermore, this conserved telomeric HSA4q35 syntenic group maps proximal to the myd mutation and is flanked by genes with homologs on HSA8p22. At the proximal boundary of the MMU8 linkage group we have identified a single 300-kb YAC containing the genes Frgl and Pcml, which have human homologs on 4q35 and 8p22, respectively. Thus, this YAC spans an evolutionary chromosomal breakpoint. As well as providing clues about chromosomal evolution, this map of the FSHD syntenic mouse region should prove invaluable in the isolation of candidate genes for this disease. Received: 20 January 1998 / Accepted: 10 April 1998     

Isolation and Chromosomal Mapping of a Mouse Homolog of the Batten Disease GeneCLN3

We describe the isolation and chromosomal mapping of a mouse homolog of the Batten disease gene,CLN3.Like its human counterpart, the mouse cDNA contains an open reading frame of 1314 bp encoding a predicted protein product of 438 amino acids. The mouse and human coding regions are 82 and 85% identical at the nucleic acid and amino acid levels, respectively. The mouse gene maps to distal Chromosome 7, in a region containing genes whose homologs are on human chromosome 16p12, whereCLN3maps. Isolation of a mouseCLN3homolog will facilitate the creation of a mouse model of Batten disease.