Double minutes in the papillary thyroid cancer cell line PTC-1113A

The cell line PTC-1113A was established from a metastasizing recurrent papillary thyroid cancer. The cell line was growing as monolayer and showed a complex karyotype with chromosome numbers ranging from 30 to 140/metaphase. A proportion of metaphases contained double minutes and/or pulverized chromosomes. Extrachromosomal DNA seemed to originate from a B-group chromosome. A chromosome 4 painting probe hybridized to extrachromosomal material, representing double minutes (dmin) and possibly minutes. In addition, fluorescence in situ hybridization (FISH) with the chromosome 4 library detected a translocation chromosome and a pulverized chromosome originating from chromosome 4. PTC-1113A is, to our knowledge, the single papillary thyroid cancer cell line demonstrating evidence of gene amplification.

Molecular cloning and functional expression of mouse connexin-30,a gap junction gene highly expressed in adult brain and skin

A new gap junction gene isolated from the mouse genome codes for a connexin protein of 261 amino acids. Because of its theoretical molecular mass of 30.366 kDa, it is named connexin-30. Within the connexin gene family, this protein is most closely related to connexin-26 (77% amino acid sequence identity). The coding region of mouse connexin-30 is uninterrupted by introns and is detected in the mouse genome as a single copy gene that is assigned to mouse chromosome 14 by analysis of mouse x hamster somatic cell hybrids. Abundant amounts of connexin-30 mRNA (two transcripts of 2.0 and 2.3 kilobase pairs) were found after 4 weeks of postnatal development in mouse brain and skin. Microinjection of connexin-30 cRNA into Xenopus oocytes induced formation of functional gap junction channels that gated somewhat asymmetrically in response to transjunctional voltage and at significantly lower voltage (Vo = +38 and -46 mV) than the closely homologous connexin-26 channels (Vo = 89 mV). Heterotypic pairings of connexin-30 with connexin-26 and connexin-32 produced channels with highly asymmetric and rectifying voltage gating, respectively. This suggests that the polarity of voltage gating and the cationic selectivity of connexin-30 are similar to those of its closest homologue, connexin-26.

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 approximately 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.

Characterization of the mouse loricrin gene: linkage with profilaggrin and the flaky tail and soft coat mutant loci on chromosome 3

Loricrin is the major component of a specialized structure, termed the cornified cell envelope, that is formed beneath the plasma membrane of stratified squamous epithelial cells and is coexpressed with profilaggrin in terminally differentiating epidermal keratinocytes. Full-length cDNAs for both mouse and human loricrin have been cloned and characterized, as has the human gene. Here we report the isolation and characterization of the mouse loricrin gene. The gene has a simple structure consisting of a single intron of 1091 bp within the 5' noncoding sequence and an uninterrupted open reading frame. Using PCR analyses of DNAs isolated from mouse x Chinese hamster somatic cell hybrids, we have mapped both the loricrin and the profilaggrin genes to chromosome 3. Genetic linkage analysis has shown that mouse loricin and profilaggrin lie within 1.5 +/- 1.1 centimorgans of each other. We have further shown that both genes map in the vicinity of the flaky tail (ft) and soft coat (soc) loci. These mouse mutants exhibit a number of changes in their integument, suggesting that abnormalities in these genes may contribute to the mutant phenotype.

Chromosomal aberrations in two adrenocortical tumors, one with a rearrangement at 11p15

Adrenocortical tumors are detected with increasing frequency, but symptomatic cases with excessive hormone production are rare. We investigated cytogenetically one benign aldosterone-producing tumor (Conn Syndrome)(case 1) and one malignant cortisol-producing tumor (Cushing Syndrome)(case 2). Radioimmunoassay of cell culture supernatant of case 2 detected cortisol secretion during 2 months in culture. Flow cytometry of spill-out cells from case 2 showed a bimodal pattern (DNA Index 1.0, 1.4). Case 1 revealed a marker chromosome in 4/25 cells analyzed; the marker was a long acrocentric partially derived from chromosome 2,der(2q). In case 2, a cytogenetic harvest was achieved after prolonged culture time (6 weeks) and a marker chromosome, add(11)(p15), was detected in 16/22 cells. A breakpoint of 11p13, as well as loss of heterozygosity of alleles on 11p15, has been reported in the literature for other malignant adrenocortical cancers.

Chromosomal assignments of mouse genes for connexin 50 and connexin 33 by somatic cell hybridization

The 12 known connexin genes coding for the subunit proteins of the gap junction channels and related in nucleotide sequence are widely dispersed in the mouse genome. By using a series of mouse X Chinese hamster somatic cell hybrids and molecular probes of murine connexin genes, we have assigned the connexin 50 gene to mouse chromosome 3. The connexin 33 gene has been mapped to the X chromosome, thus confirming the previous chromosomal assignment of this gene based on interspecific back-cross mapping.

Cloning, genomic organization, and chromosomal localization of the Scya5 gene encoding the murine chemokine RANTES

RANTES is a member of the C-C subfamily of chemokines that functions as a proinflammatory chemoattractant for CD4+ T cells, monocytes, and eosinophils, and as an activator of basophils to release histamine. Like other members of the chemokine superfamily, RANTES has been implicated in a number of chronic inflammatory and autoimmune processes based on its function and its pattern of regulation. To begin study of the transcriptional regulation of RANTES, we have determined the genomic organization of the gene encoding the small inducible cytokine A5 (Scya5) and performed an initial analysis of its promoter elements. The Scya5 gene is located on chromosome 11. By Southern blot, it is a single-copy gene approximately 4.5 kb long composed of 3 exons. This chromosomal localization and pattern of genomic organization is conserved among the other C-C subfamily of chemokines. Primer extension analysis was used to identify the transcriptional initiation site that is located 27 bp downstream of a typical TATAA box. Sequence analysis of 1040 bp 5' to the start site of the Scya5 gene revealed a number of regulatory motifs that are also shared among the chemokine family including a PU.1 box, a NF-kappa B, and an IFN regulatory factor-1 response element. This region of genomic DNA was also cloned into a luciferase reporter vector. Transfection of this reporter construct into murine proximal tubular cells reveals that TNF-alpha can induce a transcriptional activation of the gene, as would be predicted from the rise in mRNA transcripts encoding RANTES in cells stimulated with TNF-alpha.

Cloning, genomic organization, and chromosomal localization of the Scya5 gene encoding the murine chemokine RANTES

RANTES is a member of the C-C subfamily of chemokines that functions as a proinflammatory chemoattractant for CD4+ T cells, monocytes, and eosinophils, and as an activator of basophils to release histamine. Like other members of the chemokine superfamily, RANTES has been implicated in a number of chronic inflammatory and autoimmune processes based on its function and its pattern of regulation. To begin study of the transcriptional regulation of RANTES, we have determined the genomic organization of the gene encoding the small inducible cytokine A5 (Scya5) and performed an initial analysis of its promoter elements. The Scya5 gene is located on chromosome 11. By Southern blot, it is a single-copy gene approximately 4.5 kb long composed of 3 exons. This chromosomal localization and pattern of genomic organization is conserved among the other C-C subfamily of chemokines. Primer extension analysis was used to identify the transcriptional initiation site that is located 27 bp downstream of a typical TATAA box. Sequence analysis of 1040 bp 5' to the start site of the Scya5 gene revealed a number of regulatory motifs that are also shared among the chemokine family including a PU.1 box, a NF-kappa B, and an IFN regulatory factor-1 response element. This region of genomic DNA was also cloned into a luciferase reporter vector. Transfection of this reporter construct into murine proximal tubular cells reveals that TNF-alpha can induce a transcriptional activation of the gene, as would be predicted from the rise in mRNA transcripts encoding RANTES in cells stimulated with TNF-alpha.

Characterization of the mouse haptoglobin gene

Plasmids containing mouse cDNA encoding haptoglobin, a major plasma protein that binds free hemoglobin, have been isolated and characterized. The amino acid sequence predicted by the mouse haptoglobin cDNA was 80% identical to human haptoglobin and 90% identical to rat haptoglobin sequence. The mouse haptoglobin probe was used to demonstrate a single haptoglobin gene in the genome of C57BL6 mice mapped to chromosome 8. Sequence analysis of the mouse Hp gene promoter revealed two unique features: the presence of a second TATA box with a 48-bp trinucleotide repeat immediately upstream. The enhancer element and the sequences shown to be required for cytokine and hormonal regulation of the rat Hp gene are highly conserved in mouse. Interestingly, the single nucleotide variation G to A, which completely inactivates the IL-6 responsive element A in the rat Hp gene, is identical in mouse. This suggests that the presence of an inactive IL-6-responsive element A in Hp genes is common in rodents.

Chromosomal aberrations in two sporadic gastrinomas

Results of cell culture and cytogenetic analysis (standard and fluorescent in situ hybridization, FISH) of two sporadic gastrinomas are reported. Maintenance of hormonal activity was assessed by detection of gastrin levels during the first 3 months in culture. Case 1 showed clonal aberrations consisting of two marker chromosomes: marker 1 is a large metacentric chromosome and marker 2 is a small acrocentric chromosome. Case 2 showed a constitutional polymorphism with chromosome 15p+ and a clone in the tumor cell culture with trisomy for chromosome 3. To our knowledge, this is the first cytogenetic report of sporadic gastrinomas (Zollinger-Ellison syndrome).

Assignment of the mouse tartrate-resistant acid phosphatase gene (Acp5) to chromosome 9

Tartrate-resistant acid phosphatase is a marker enzyme for osteoclasts, the multinucleated cell responsible for bone resorption. Interspecific somatic whole cell hybrids and karyotypically simple microcell hybrids were used to map the gene encoding tartrate-resistant acid phosphatase (Acp5) to mouse Chromosome 9. Acp5 is therefore a member of a syntenic family of genes that map to human chromosome 19p13.1-p13.3 and mouse Chromosome 9.

Mox-1 and Mox-2 define a novel homeobox gene subfamily and are differentially expressed during early mesodermal patterning in mouse embryos

We have isolated two mouse genes, Mox-1 and Mox-2 that, by sequence, genomic structure and expression pattern, define a novel homeobox gene family probably involved in mesodermal regionalization and somitic differentiation. Mox-1 is genetically linked to the keratin and Hox-2 genes of chromosome 11, while Mox-2 maps to chromosome 12. At primitive streak stages (approximately 7.0 days post coitum), Mox-1 is expressed in mesoderm lying posterior of the future primordial head and heart. It is not expressed in neural tissue, ectoderm, or endoderm. Mox-1 expression may therefore define an extensive ‘posterior’ domain of embryonic mesoderm before, or at the earliest stages of, patterning of the mesoderm and neuroectoderm by the Hox cluster genes. Between 7.5 and 9.5 days post coitum, Mox-1 is expressed in presomitic mesoderm, epithelial and differentiating somites (dermatome, myotome and sclerotome) and in lateral plate mesoderm. In the body of midgestation embryos, Mox-1 signal is restricted to loose undifferentiated mesenchyme. Mox-1 signal is also prominent over the mesenchyme of the heart cushions and truncus arteriosus, which arises from epithelial-mesenchymal transformation and over a limited number of craniofacial foci of neural crest-derived mesenchyme that are associated with muscle attachment sites. The expression profile of Mox-2 is similar to, but different from, that of Mox-1. For example, Mox-2 is apparently not expressed before somites form, is then expressed over the entire epithelial somite, but during somitic differentiation, Mox-2 signal rapidly becomes restricted to sclerotomal derivatives. The expression patterns of these genes suggest regulatory roles for Mox-1 and Mox-2 in the initial anterior-posterior regionalization of vertebrate embryonic mesoderm and, in addition, in somite specification and differentiation.

Significance of trisomy 7 in thyroid tumors

Standard cytogenetic studies of a multifocal metastasizing papillary thyroid carcinoma revealed two clonal chromosome aberrations: rearranged 10q and trisomy 7. Trisomy 7 seemed to be restricted to tumor nodule A, whereas era (10q) was detected in tumor nodule B and in a metastatic lymph node. We applied fluorescent in situ hybridization to ask whether trisomy 7 was a feature of the original tumor nodule or an in vitro phenomenon changing quantitatively during early passages and to see whether trisomy 7 was restricted to tumor nodule A. We used the biotinylated chromosome 7 alpha-satellite probe D7Z1 on freshly dropped slides from metaphase harvests from tumor nodule A,B, and the lymph node and on touch preparations from the frozen specimen of tumor nodule A. Trisomy 7 was present in the original tumor nodule (6% of cells), as well as in early passages (P1-3) from both tumor nodules and the metastatic lymph node with a frequency of 10.7-13.2%. The detection of trisomy 7 as a stable component in short-term cell culture and its presence in the original tumor material indicates that this common numerical aberration is an in vivo phenomenon.

Two gap junction genes, connexin 31.1 and 30.3, are closely linked on mouse chromosome 4 and preferentially expressed in skin

Two new gap junction genes isolated from the mouse genome code for connexin homologues of 271 and 266 amino acids, designated here Cx31.1 and Cx30.3, respectively. The two open reading frames, oriented in the same direction, are only 3.4 kb apart on mouse chromosome 4. Within the connexin family, these two proteins are most closely related to one another (70% amino acid sequence identity) and to Cx31 (65 and 68% identity, respectively). Comparison of the Cx31.1 mouse gene with a Cx31.1 cDNA showed a similar genomic organization to that found with other members of the connexin gene family, i.e. the coding and 3'-untranslated regions are contained within a single exon, which is preceded by an intron, less than 25 bases upstream of the ATG start codon. Northern blot hybridization revealed highly tissue-specific coexpression of the 1.6-kb Cx31.1 mRNA and two Cx30.3 transcripts of 1.9- and 3.2-kb size, predominantly in skin and two related mouse keratinocyte cell lines. Minor levels of Cx31.1 mRNA were detected in testis. Microinjection of Cx30.3, but not Cx31.1 cRNA, into Xenopus oocyte pairs induced formation of functional gap junction channels with unique voltage-gated parameters compared to other connexins expressed similarly.

Mouse UDP-GlcNAc: dolichyl-phosphate N-acetylglucosaminephosphotransferase. Molecular cloning of the cDNA, generation of anti-peptide antibodies and chromosomal localization

A cDNA encoding UDP-GlcNAc-dolichyl-phosphate N-acetylglucosaminephosphotransferase (GPT; EC 2.7.8.15), an enzyme that catalyses the first step in the synthesis of dolichol-linked oligosaccharides, was isolated from mRNA prepared from mouse mammary glands. The cDNA contains an open reading frame that codes for a protein of 410 amino acids with a predicted molecular mass of 46.472 kDa. Mouse GPT has two copies of a putative dolichol-recognition sequence that has so far been identified in all eukaryotic enzymes which interact with dolichol, and four consensus sites for asparagine-linked glycosylation. It shows a high degree of conservation with yeast and hamster GPTs at the amino acid level. The mouse GPT cDNA recognized a single mRNA species of about 2 kb in mouse mammary glands when used as a probe in Northern blot analysis. An antiserum raised against a 15-residue peptide, derived from the predicted amino acid sequence of the cloned mouse cDNA, specifically precipitated the activity of GPT from solubilized mouse mammary gland microsomes, and detected a protein of about 48 kDa on Western blot. This size is in good agreement with that predicted from the cDNA sequence, and also with that (46 and 50 kDa) of purified bovine GPT. With the use of a panel of mouse/hamster somatic-cell hybrids and a specific probe derived from the 3'-non-coding region of the mouse cDNA, the GPT gene was mapped to mouse chromosome 17.

Chromosomal assignments of mouse connexin genes, coding for gap junctional proteins, by somatic cell hybridization

The connexin genes Cx31 and Cx45 coding for proteins of gap junctional subunits have been assigned to mouse chromosomes 4 and 11 by Southern blot hybridization of specific gene probes to DNA from mouse x Chinese hamster somatic cell hybrids. In addition, our results confirm the recent assignment of mouse connexin genes Cx26, Cx32, Cx37, Cx40, Cx43, and Cx46 to mouse chromosomes 14, X, 4, 3, 10, and 14, respectively, by analysis of interspecific backcrosses and by somatic cell hybridization. Our assignment of the Cx31 gene to mouse chromosome 4 locates the fourth connexin gene on this mouse chromosome to which the genes for Cx31.1, Cx37, and Cx30.3 have previously been assigned. Interestingly three of them (coding for Cx31, Cx31.1, and Cx30.3) are preferentially expressed in skin. Possibly some of the connexin genes clustered on mouse chromosome 4 may be regulated coordinately.

Assignment of tyrosine-specific T-cell phosphatase to conserved syntenic groups on human chromosome 18 and mouse chromosome 18

Phosphorylation of proteins on tyrosine is crucially involved in signal transduction and mitogenesis and is regulated by both kinases and phosphatases. Recently, a number of soluble and transmembrane receptor-linked protein tyrosine phosphatases (PTPase) have been characterized. Among these is a 48.4-kDa PTPase encoded by a cDNA isolated from a T-lymphocyte library by low-stringency screening with probes derived from placental PTPase 1B. A human T-cell PTPase (PTPT) cDNA and somatic cell hybrids were used to assign a PTPT gene to conserved syntentic groups on human chromosome 18 and on mouse chromosome 18. Two unlinked sequences, one on human chromosome 1, were also detected.

Genetic markers in thyroid tumors

Tissue from nine patients with malignant tumors and two with benign tumors was cultured briefly before cytogenetic analysis. The tumors included one goiter and one Hürthle cell adenoma, one lymphoma, one medullary carcinoma, two Hürthle cell cancers, and five papillary cancers, varying widely in clinical staging and histologic differentiation. When assessed, DNA content was aneuploid in two of six malignant tumors. Various culture conditions (oxygen levels, dissociation methods, and media) were evaluated; the end points were growth, cell differentiation, and time to first harvest. Clonal aberrations were detected in one of four successfully harvested papillary cancers: they consisted of trisomy 7 and a rearrangement of chromosome 10. The rea (10) seen in 22 of 27 cells involved bands q11-21. Two other papillary tumors and a medullary cancer (a family member with multiple endocrine neoplasia type IIA) showed tetraploidy and nonclonal numerically aberrant cells. A lymphoma and two benign lesions showed no cytogenetic abnormality. The tumor with rea (10) is of special interest because abnormalities of 10q have been reported repeatedly in thyroid tumors, including two cases of papillary thyroid tumors with a structural aberration similar to that of the presented case. This rearrangement could affect the ret-proto-oncogene, localized to 10q11.2 which is activated in some papillary thyroid carcinomas.

Chromosomal assignment in mouse of matrix Gla protein and bone Gla protein genes

Matrix Gla protein (MGLAP) and bone Gla protein (BGLAP) are calcium-binding, vitamin K-dependent proteins produced by cells of the osteoblastic lineage. Sequence homology suggests that the genes for these proteins evolved from a common ancestor. Somatic whole cell hybrids and karyotypically simple microcell hybrids were used to map Mglap to mouse Chromosome 6 and Bglap to mouse Chromosome 3. Human MGLAP has previously been mapped to chromosome 12p, a region with homology to mouse Chromosome 6, and human BGLAP has been mapped to chromosome 1q, a region with homology to mouse Chromosome 3. It appears that BGLAP is the third calcium-binding protein that maps to human chromosome 1q and mouse Chromosome 3.

Assignment of the human gene for the alpha 1 subunit of the cardiac DHP-sensitive Ca2+ channel (CCHL1A1) to chromosome 12p12-pter

A human clone corresponding to the gene encoding the alpha 1 subunit of the cardiac dihydropyridine-sensitive calcium channel (CCHL1A1) has been isolated and partially sequenced. Oligonucleotides based on the human sequence were constructed and used in the polymerase chain reaction to amplify specifically this human gene in human-rodent somatic cell hybrids. Using somatic cell hybrids that contained defined regions of human chromosome 12, the human alpha 1 subunit of the cardiac dihydropyridine-sensitive calcium channel has been assigned to the short arm of chromosome 12 in the interval 12p12-pter.

Mouse platelet-derived growth factor receptor alpha gene is deleted in W19H and patch mutations on chromosome 5

The mouse W19H mutation is an x-ray-induced deletion of more than 2 centimorgans on chromosome 5 encompassing the white spotting mutation W (encoded by the Kit protooncogene), patch (Ph), and recessive lethal (l) loci. The platelet-derived growth factor receptor alpha gene (PDGFRA) like Kit encodes a transmembrane receptor tyrosine kinase. By using mouse-Chinese hamster somatic cell hybrids and haplotype analysis in interspecific backcross mice, mouse Pdgfra was mapped to chromosome 5 in tight linkage with Kit. Hybridization of a PDGFRA probe to DNAs from W19H/ + heterozygous mice and patch heterozygous mice, and their wild-type littermates, demonstrated deletion of Pdgfra. Pulsed-field gel electrophoresis indicated that Kit and Pdgfra are linked on a 630-kilobase Mlu I DNA fragment. Thus the W19H deletion removes at least two receptor tyrosine kinases and the results suggest Pdgfra as a candidate for the Ph locus.

Zinc finger protein gene complexes on mouse chromosomes 8 and 11

Two murine homologs of the Drosophila Krüppel gene, a member of the gap class of developmental control genes that encode a protein with zinc fingers, were mapped to mouse chromosomes 8 and 11 by using somatic cell hybrids and an interspecific backcross. Surprisingly, both genes were closely linked to two previously mapped, Krüppel-related zinc finger protein genes, suggesting that they are part of gene complexes.

Gene mapping of mouse laminin A and B2 subunits using mouse-Chinese hamster somatic cell hybrids

Laminin is a multichain extracellular matrix glycoprotein found primarily in basement membranes. The molecule is made up of three subunits, designated as A, B1, and B2. Using an 850-base cDNA probe for the mouse laminin A-chain and a 1000-base cDNA probe for the mouse laminin B2 chain, we have screened mouse-Chinese hamster somatic cell hybrids in order to assign the genes for each of these polypeptides to their respective mouse chromosome. We have determined that the mouse laminin B2-chain gene is located on chromosome 1 (confirming this assignment) and the laminin A-chain gene is located on chromosome 17.

Mapping and conservation of the group-specific component gene in mouse

The group-specific component (GC), also known as the vitamin D-binding protein, transports vitamin D and its metabolites in plasma to target tissues throughout the body. The GC gene shares an evolutionary origin with genes encoding albumin (ALB) and alpha-fetoprotein (AFP). All three genes are descendants of an evolutionary ancestor that arose from an intragenic triplication. As a result, each gene is composed of three homologous domains. The study described here characterizes and compares mouse GC to the corresponding nucleotide and amino acid sequences of GC from human and rat. The deduced amino acid sequence of mouse GC was 78% identical to human and 91% identical to rat GC. The results suggest that, unlike the corresponding sequences in the ALB and AFP genes, chromosomal sequences encoding the first domain and the leader sequence of the GC gene have specifically been conserved throughout vertebrate evolution. Protection of domain I during evolution may correlate with an important functional aspect of its sequence. The mouse GC gene was mapped to chromosome 5, where the ALB and AFP genes are also located, demonstrating conservation of the three genes in vertebrate species.

Clustering of cytokine genes on mouse chromosome 11

The presence of positionally conserved amino acid residues suggests that the mouse proteins TCA3, P500, MIP1-alpha, MIP1-beta, and JE are members of a single gene family. These proteins are activation specific and can be expressed by both myeloid and lymphoid cells. MIP1-alpha/MIP1-beta and MCAF (the putative human homologue of JE) act as chemotactic and activating agents for neutrophils and macrophages, respectively. The functions of TCA3 and P500 are unknown. We have used interspecies somatic cell hybrids and recombinant inbred mouse strains to show that the genes encoding TCA3, MIP1-alpha, MIP1-beta, and JE (provisionally termed Tca3, Mip-1a, Mip-1b, and Sigje, respectively) map as a cluster on the distal portion of mouse chromosome 11 near the Hox-2 gene complex. DNA sequence analysis indicates that the P500 and TCA3 proteins are encoded by alternative splicing products of one genomic gene. Additionally, the genes encoding TCA3 and JE are found to be strikingly similar with respect to the positions of intron-exon boundaries. Together, these data support the model that the cytokines TCA3, P500, MIP1-alpha, MIP1-beta, and JE are encoded by a single cluster of related genes. The gene encoding IL-5 (Il-5), which acts as a T cell-replacing factor, a B cell growth factor, and an eosinophil differentiation factor, is also mapped to mouse chromosome 11.Il-5 maps approximately 25 cM proximal to the Tca-3 gene and appears tightly linked to a previously described gene cluster that includes Il-3, Il-4, and Csfgm. We discuss the potential relevance of the two cytokine gene clusters described here with particular attention to specific human hematologic malignancies associated with chromosomal aberrations at corresponding locations on human chromosomes 5 and 17.

Gene for parathyroid hormone-like peptide is on mouse chromosome 6

The single-copy parathyroid hormone-like peptide gene (Pthlh) was assigned to mouse chromosome 6 using a rat PTHLH cDNA as hybridization probe in the Southern blot analysis of DNAs isolated from a panel of mouse x Chinese hamster cell hybrids. The mouse parathyroid hormone gene (Pth) has previously been assigned to mouse chromosome 7 and the PTHLH and PTH genes have also been shown to be on different chromosomes in human and rat. Therefore, despite significant amino-terminal sequence homology between the PTHLH and PTH peptides, as well as similarities in the structural organization of the human PTHLH and PTH genes, the genes encoding these peptides have discrete chromosomal locations in the mouse, rat, and man.

Regional assignment of the mouse alpha A2-crystallin gene (Crya-1) to chromosome 17A3----B by in situ hybridization

Previously, we assigned the alpha A2-crystallin (Crya-1) structural gene to mouse chromosome 17 via Southern blot hybridization analysis of mouse x Chinese hamster somatic cell hybrids. Using in situ hybridization, we have now localized this gene to 17A3----B, a subchromosomal region containing several genes whose linkage relationships have been shown to be conserved on human chromosome 6. In man, however, the homologous gene (CRYA1) is located on human chromosome 21, indicating that internal rearrangements can occur within highly conserved chromosomal regions during the divergence of man and mouse.

I/Lyn mouse phosphorylase kinase deficiency: mutation disrupts expression of the alpha/alpha'-subunit mRNAs

A cDNA encoding the alpha subunit of mouse skeletal muscle phosphorylase kinase was used to compare the expression of alpha mRNAs in normal and phosphorylase kinase-deficient tissues of the I/Lyn mouse. The results demonstrate that two different molecular weight species of poly(A)+ RNA in normal mouse heart and skeletal muscle hybridize to the alpha cDNA. These two mRNAs direct the synthesis of alpha protein and its isoform alpha' in a cell-free translation system. Thus, alpha and alpha' are encoded by two distinct mRNAs. The abundance of both of these mRNAs is reduced dramatically in the phosphorylase kinase-deficient skeletal muscle and heart tissues from the I/Lyn mouse strain. This result indicates that a mechanism common to both alpha and alpha' expression is disrupted by the I/Lyn mutation. The I/Lyn deficiency is inherited as an X chromosome trait. By Southern mapping of Chinese hamster-mouse cell hybrids the alpha gene was localized to the mouse X chromosome, supporting the possibility that the I/Lyn mutation is in the alpha gene. These results are discussed in terms of a cis or trans mutation influencing the expression of either a single alpha/alpha' gene or two genes encoding alpha and alpha'.

A family of type I keratin genes and the homeobox-2 gene complex are closely linked to the rex locus on mouse chromosome 11

Type I and type II keratins are major constituents of intermediate filaments that play a fundamental role in the cytoskeletal network. By using both somatic cell hybrids and conventional and interspecific linkage crosses, several genes encoding type I keratins, including the epidermal keratin K10, were shown to be closely linked to the homeobox-2 complex and the rex locus on mouse chromosome 11. The absence of crossovers between type I keratin-encoding genes and rex (N = 239), a locus affecting hair development, raises the possibility that mutations at rex and neighboring loci affecting skin and hair development involve type I keratin genes.

Mouse melanoma growth stimulatory activity gene (Mgsa) is polymorphic and syntenic with the W, patch, rumpwhite, and recessive spotting loci on chromosome 5

Melanoma growth stimulatory activity (Mgsa) is a polypeptide growth factor originally detected in culture medium of the human malignant melanoma cell line Hs294T and may have an autocrine role in neoplastic growth. Mgsa is a member of the small inducible gene (SIG) family and shares homology with beta-thromboglobulin and platelet factor 4. Mgsa was localized to chromosome 5 using a cDNA probe for mouse Mgsa and somatic cell hybrids and is thus syntenic with Kit (W), Ph, Rw, and rs loci. The results eliminate Mgsa as the product of the Steel locus on chromosome 10, but raise the possibility that Mgsa might be synonymous with a chromosome 5 locus affecting skin pigmentation.

Assignment of retinoblastoma susceptibility gene to mouse chromosome 14

A human cDNA probe was used to screen a panel of mouse-Chinese hamster somatic cell hybrids to determine the chromosomal location of the retinoblastoma susceptibility gene (Rb-1) in mouse. The Rb-1 gene mapped to mouse chromosome 14. Thus, the retinoblastoma susceptibility gene is syntenic with esterase 10 (the mouse homolog of human esterase D). The chromosomal assignment of the mouse Rb-1 gene was further confirmed by using the same probe to study mouse-rat microcell hybrids. Since the human retinoblastoma susceptibility gene (RB1) along with the gene for esterase D is on chromosome 13q14, these data indicate this linkage group is conserved in man and mouse.

Sigje, a member of the small inducible gene family that includes platelet factor 4 and melanoma growth stimulatory activity, is on mouse chromosome 11

Stiles and coworkers originally identified a gene they termed JE that is transcriptionally activated in mouse fibroblasts early after treatment with platelet derived growth factor or serum. This gene, now named Sigje, can encode a 148-amino acid secreted, basic polypeptide that belongs to the small inducible gene (SIG) family whose members include, for example, platelet factor 4, melanoma growth stimulatory activity (Mgsa), and interferon inducible protein 10. SIG family members share a conserved array of cysteine and proline residues and a similar predicted secondary structure, and may have evolved from a common ancestral gene. Several members of the SIG family have been assigned to the proximal long arm of human chromosome 4, to a region that has genetic homoeology with a portion of mouse Chromosome 5. We report here that mouse Sigje, in contrast to Mgsa, is on Chromosome 11. Sigje restriction fragment length polymorphisms in Mus spretus DNA were identified with the enzymes TaqI, MspI, BclI, and XbaI, and will be useful in mapping by meiotic recombination.

Mapping of mouse gamma crystallin genes on chromosome 1

Restriction fragments analysis of DNA from mouse-hamster somatic-cell hybrid clones revealed that a mouse gamma crystallin cDNA hybridized to genomic sequences located on mouse chromosome 1. Identification of restriction fragment length polymorphisms (RFLPs) in the gamma crystallin sequences of inbred strains of mice permitted the further localization of the gamma crystallin genes (Cryg) to the proximal region of chromosome 1 closely linked to the loci encoding isocitrate dehydrogenase (Idh-1), a low molecular weight (LM) crystallin protein polymorphism (Len-1), and fibronectin (Fn-1). A single recombinant was observed between Len-1 and an RFLP in the gamma crystallin gene family, consistent with the hypothesis that Len-1 is one of the several structural loci encoding gamma crystallin genes. Len-1 is probably located on the centromeric end of the Cryg gene family. Linkage of Idh-1, Cryg, and Fn-1 in mice extends the syntenic relationship of those loci to the human, bovine, and rodent genomes and may define a chromosomal region that is generally conserved among mammals. The map position of Cryg, near the eye lens obsolescence (Elo) locus, was confirmed by the discovery that the restriction fragment patterns of gamma crystallin sequences differed between strain C3H/HeJ and the congenic anophthalmic mutant strain, C3H.Elo. Therefore, the gamma crystallin genes were cotransferred with the mutant Elo gene in the derivation of C3H.Elo. The results establish that LEN-1 is a marker for the gamma crystallin gene family, position the gamma crystallin gene family relative to other markers on mouse chromosome 1, and provide additional evidence that the Elo mutation is encoded at a locus closely linked to the gamma crystallin gene cluster. This study found no evidence of recombination hot spots within the gamma crystallin gene cluster.

Chromosome assignment of mouse insulin, colony stimulating factor 1, and low-density lipoprotein receptors

Receptors for insulin, low-density lipoprotein, and colony stimulating factor 1 are associated with diabetes, atherosclerosis, and cancer in man. Complementary DNA clones for Insr, Ldlr, and Csfmr were used to chromosomally assign the three genes in mouse. In contrast to their close linkage on the short arm of human Chromosome 19, Insr and Ldlr are asyntenic, residing on mouse Chromosomes 8 and 9, respectively. The genes for CSF1R, CSF1, CSF2, IL-3, and IL-5 form a cluster on the long arm of human Chromosome 5. In mouse, Csfm, Csfgm, and IL-3 are syntenic on Chromosome 11. The Csfmr gene was assigned to mouse Chromosome 18 and is thus unlinked to other members of this gene cluster. These gene assignments provide additional topographical information on conservation of linkage groups in man and mouse and provide a genetic framework for evaluating the possible roles for the three receptor genes in genetic diseases in mouse.

Isolation of a cDNA that encodes the peptide core of the secretory granule proteoglycan of rat basophilic leukemia-1 cells and assessment of its homology to the human analogue

It has been previously shown that a single gene is used to encode the peptide core of the extracellular proteoglycan of rat L2 yolk sac tumor cells and the intracellular proteoglycan of rat basophilic leukemia (RBL)-1 cells. In order to determine if the predicted amino acid sequences of these proteoglycans are identical as well as to isolate a full length cDNA encoding a rat secretory granule proteoglycan, a cDNA library was prepared from RBL-1 cells and screened with the 165-base pair 5'----XmnI fragment of pPG-1, a partial cDNA which encodes the rat L2 cell proteoglycan peptide core. Based on the consensus nucleotide sequence of two full length RBL-1 cell-derived cDNAs, the 5' untranslated region of the mRNA that is expressed in RBL-1 cells is shorter than that expressed in the rat L2 cells although the coding regions of the mRNAs from the two cell types are identical. These findings indicate that the targeting of proteoglycans to an intracellular or extracellular compartment is a cell-specific event which is independent of the translated peptide core. Since the RBL-1 cell and the rat L2 cell proteoglycans have different types of glycosaminoglycans bound to them, it can also be concluded that the selection of the type of glycosaminoglycan that will be synthesized onto a peptide core is a cell-specific event which is not exclusively dependent on the translated peptide core. When the predicted amino acid sequence of the RBL-1 cell proteoglycan peptide core was compared to the predicted sequence of the homologous human molecule from HL-60 cells, 48% of the amino acids were identical. The N terminus was the most highly conserved area of the molecule. This region of the peptide core, which precedes the serine-glycine repeat region, is likely to be of critical importance for the biosynthesis and/or function of these proteoglycans. Analysis of 10 different mouse/hamster somatic cell hybrid lines with a SspI----3' fragment of the rat L2 cell cDNA revealed that, as in the human, the gene that encodes the mouse analogue of this peptide core resides on chromosome 10.

Assignment of the lactotransferrin gene to human chromosome 3 and to mouse chromosome 9

Lactotransferrin (LTF), a member of the transferrin family of genes, is the major iron-binding protein in milk and body secretions. The amino acid sequence of LTF consists of two homologous domains homologous to proteins in the transferrin family. Recent isolation of cDNA encoding mouse LTF has expedited the mapping of both mouse and human LTF genes. Southern blot analysis of DNA from mouse-Chinese hamster and human-mouse somatic cell hybrids maps the LTF gene to mouse chromosome 9 and to human chromosome 3, respectively. Furthermore, analysis of cell hybrids containing defined segments of human chromosome 3 demonstrates that the gene is located in the 3q21-qter region. These results suggest that LTF and associated genes of the transferrin family have existed together on the same chromosomal region for 300-500 million years.

Chromosomal assignments of genes for tissue plasminogen activator and urokinase in mouse

The genes encoding the two plasminogen activators, tissue plasminogen activator and urokinase, were mapped to mouse chromosomes using probes derived from the respective mouse cDNAs. DNA from mouse-Chinese hamster and mouse-rat somatic cell hybrids was digested with BamHI and EcoRI, respectively, and analyzed by Southern blot hybridization for the segregation of the two genes. Tissue plasminogen activator and urokinase cosegregated with mouse chromosomes 8 and 14, respectively. The plasminogen activator genes thus fall into two syntenic groups that are conserved in human and mouse.

Genes encoding alpha and beta subunits of Na,K-ATPase are located on three different chromosomes in the mouse

We have made use of a panel of mouse-hamster somatic cell hybrids and restriction fragment length polymorphisms between two mouse species (Mus musculus and Mus spretus) to determine the chromosomal localization of genes encoding the alpha and beta subunits of the Na,K-ATPase (Na+,K+-activated ATP phosphohydrolase, EC 3.6.1.3). DNA probes for three distinct isoforms of the Na,K-ATPase alpha subunit mapped to three different mouse chromosomes: the alpha 1 gene (Atpa-1) cosegregated with the Egf gene on chromosome 3; alpha 2 (Atpa-2) with the cytochrome P-450PB gene family/coumarin hydroxylase locus on chromosome 7; alpha 3 (Atpa-3) with the alpha-spectrin gene on chromosome 1. The Na,K-ATPase beta-subunit gene (Atpb) mapped to the same region of chromosome 1, but it was not tightly linked to the Atpa-3 gene. These results indicate that three isoforms of the Na,K-ATPase alpha subunit are encoded by three distinct genes. The dispersion of Na,K-ATPase genes suggests that their expression is not likely to be controlled by a common cis-acting regulatory element.

Expansion of the complement receptor gene family. Identification in the mouse of two new genes related to the CR1 and CR2 gene family

Human cDNA probes encoding the C3b/C4b complement receptor, CR1, have been used to identify, in the mouse, two new genes which are related to CR1 but which appear to encode a different protein product. These new mouse genes, arbitrarily designated mouse genes X and Y, hybridize specifically to three different cDNA probes derived from human CR1. The degree of hybridization homology between the mouse X and Y genes suggests they are very closely related to one another; however, the chromosomal localization of the mouse X gene to chromosome 8 and the mouse Y gene to chromosome 1 indicates they are distinct gene sequences. The mRNA species detected with the X and/or Y (X/Y) sequences are approximately 2000 bases in length, but vary in both quantity and size depending upon the tissue analyzed. DNA sequence analysis of a cDNA specific for the X and Y sequences indicates the mature protein(s) will contain the 60 amino acid consensus repeat characteristic of a group of other proteins including CR1, the C3d receptor (CR2), H, C4 binding protein (C4bp), the interleukin 2 (Il 2) receptor and others. The identity of the mouse X and Y genes, and the function of the proteins which they encode, is not known; however, the small size of the mRNA and the tissue specific expression suggests they do not encode mouse CR1 or CR2 but instead encode a related protein (or proteins) which is expressed in a wide variety of mouse tissues.

Expansion of the complement receptor gene family. Identification in the mouse of two new genes related to the CR1 and CR2 gene family

Human cDNA probes encoding the C3b/C4b complement receptor, CR1, have been used to identify, in the mouse, two new genes which are related to CR1 but which appear to encode a different protein product. These new mouse genes, arbitrarily designated mouse genes X and Y, hybridize specifically to three different cDNA probes derived from human CR1. The degree of hybridization homology between the mouse X and Y genes suggests they are very closely related to one another; however, the chromosomal localization of the mouse X gene to chromosome 8 and the mouse Y gene to chromosome 1 indicates they are distinct gene sequences. The mRNA species detected with the X and/or Y (X/Y) sequences are approximately 2000 bases in length, but vary in both quantity and size depending upon the tissue analyzed. DNA sequence analysis of a cDNA specific for the X and Y sequences indicates the mature protein(s) will contain the 60 amino acid consensus repeat characteristic of a group of other proteins including CR1, the C3d receptor (CR2), H, C4 binding protein (C4bp), the interleukin 2 (Il 2) receptor and others. The identity of the mouse X and Y genes, and the function of the proteins which they encode, is not known; however, the small size of the mRNA and the tissue specific expression suggests they do not encode mouse CR1 or CR2 but instead encode a related protein (or proteins) which is expressed in a wide variety of mouse tissues.

Gene assignments and syntenic groups in the sacred baboon (Papio hamadryas)

Eighteen genes were assigned to chromosomes in the sacred baboon, Papio hamadryas, by their concordant segregation with the chromosomes in a set of baboon X Chinese hamster somatic cell hybrids. ACY1 was assigned to P. hamadryas chromosome 2 (PHA 2); SOD1 and MDH2 to PHA 3; ME1 and SOD2 to PHA 4; NP, MPI, PKM2, and HEXA to PHA 7; PP to PHA 9; ADA and ITPA to PHA 10; LDHB and TPI1 to PHA 11; MDH1 to PHA 13; ESD to PHA 17; and GPI and PEPD to PHA 20. Regional assignments were possible for ACY1 (PHA 2pter----q1) and MDH2 and SOD1 (PHA 3p). Five other independently segregating markers or syntenic groups (PGD, PGM1; and PEPC; PGM2 and PEPS; IDH1; LDHA and ACP2; and GSR) were also identified. Gene assignments and syntenic groups described in P. hamadryas are compared to those found in P. papio, the rhesus monkey, and man. A possible primate model for human lymphoid disease is discussed.

Mapping polypeptide hormone genes in the mouse: somatostatin, glucagon, calcitonin, and parathyroid hormone

Mouse-Chinese hamster hybrids segregating mouse chromosomes were analyzed by Southern hybridization techniques to map the genes for somatostatin (Smst), glucagon (Gcg), calcitonin (Calc), and parathyroid hormone (Pth). The mouse gene for somatostatin, detected on a 20-kb EcoRI fragment, is located on mouse chromosome 16. Glucagon cDNA hybridized to a 14-kb EcoRI fragment residing on chromosome 2. Calcitonin and parathyroid hormone genes, detected on 7.8-kb HindIII and 6.0-kb BamHI fragments, respectively, were on mouse chromosome 7. The calcitonin and parathyroid hormone genes appear to be part of a larger linkage group which has been conserved in mouse and man.