RESUMEN
The tilted (tlt) mouse carries a recessive mutation causing vestibular dysfunction. The defect in tlt homozygous mice is limited to the utricle and saccule of the inner ear, which completely lack otoconia. Genetic mapping of tlt placed it in a region orthologous with human 4p16.3-p15 that contains two loci, DFNA6 and DFNA14, responsible for autosomal dominant, nonsyndromic hereditary hearing impairment. To identify a possible relationship between tlt in mice and DFNA6 and DFNA14 in humans, we have refined the mouse genetic map, assembled a BAC contig spanning the tlt locus, and developed a comprehensive comparative map between mouse and human. We have determined the position of tlt relative to 17 mouse chromosome 5 genes with orthologous loci in the human 4p16.3-p15 region. This analysis identified an inversion between the mouse and human genomes that places tlt and DFNA6/14 in close proximity.
Asunto(s)
Sordera/genética , Membrana Otolítica/anomalías , Mapeo Físico de Cromosoma , Vestíbulo del Laberinto/fisiología , Animales , Mapeo Cromosómico , Cromosomas Humanos Par 4/genética , Mapeo Contig , Etiquetas de Secuencia Expresada , Humanos , Ratones , Ratones Endogámicos C57BL , Repeticiones de Microsatélite , Datos de Secuencia Molecular , Mutación , Vestíbulo del Laberinto/anomalíasRESUMEN
Radiation hybrid (RH) mapping of the mouse genome provides a useful tool in the integration of existing genetic and physical maps, as well as in the ongoing effort to generate a dense map of expressed sequence tags. To facilitate functional analysis of mouse Chromosome 5, we have constructed a high-resolution RH map spanning 75 cM of the chromosome. During the course of these studies, we have developed RHBase, an RH data management program that provides data storage and an interface to several RH mapping programs and databases. We have typed 95 markers on the T31 RH panel and generated an integrated map, pooling data from several sources. The integrated RH map ranges from the most proximal marker, D5Mit331 (Chromosome Committee offset, 3 cM), to D5Mit326, 74.5 cM distal on our genetic map (Chromosome Committee offset, 80 cM), and consists of 138 markers, including 89 simple sequence length polymorphic markers, 11 sequence-tagged sites generated from BAC end sequence, and 38 gene loci, and represents average coverage of approximately one locus per 0.5 cM with some regions more densely mapped. In addition to the RH mapping of markers and genes previously localized on mouse Chromosome 5, this RH map places the alpha-4 GABA(A) receptor subunit gene (Gabra4) in the central portion of the chromosome, in the vicinity of the cluster of three other GABA(A) receptor subunit genes (Gabrg1-Gabra2-Gabrb1). Our mapping effort has also defined a new cluster of four genes in the semaphorin gene family (Sema3a, Sema3c, Sema3d, and Sema3e) and the Wolfram syndrome gene (Wfs1) in this region of the chromosome.
Asunto(s)
Mapeo Cromosómico/métodos , Cromosomas Humanos Par 5 , Semaforina-3A , Animales , Proteínas Portadoras/genética , Factores Quimiotácticos/genética , Cromosomas Humanos Par 5/genética , Bases de Datos Factuales , Marcadores Genéticos , Glutatión Sintasa/genética , Humanos , Células Híbridas , Ratones , Familia de Multigenes/genética , Proteínas del Tejido Nervioso/genética , Canales de Potasio/genética , Canales de Potasio de Dominio Poro en Tándem , Receptores de GABA-A/genética , Lugares Marcados de Secuencia , Programas InformáticosRESUMEN
The ability to sense gravity is enhanced by an extracellular structure that overlies the macular sensory epithelium. This complex consists of high density particles, otoconia, embedded within a gelatinous membrane. The tilted mouse specifically lacks otoconia, yet has no other detectable anatomic lesions. Furthermore, the penetrance of the tilted phenotype is nearly 100%. This mouse provides a model to identify genes that are involved in the development and function of vestibular otoconia. Using SSLP markers, we have mapped the tilted (tlt) gene on mouse Chromosome (Chr) 5 between D5Mit421 and D5Mit353/D5Mit128/D5Mit266/D5Mit267 by analysis of the progeny of an intersubspecific F2 intercross. We also mapped the fibroblast growth factor receptor 3 (Fgfr3) gene, a potential candidate for tlt, and the Huntington's disease homolog (Hdh) gene to D5Mit268, approximately 4.3 centiMorgans (cM) from the tilted locus. This study excludes both Fgfr3 and Hdh as candidate genes for tlt and identifies closely linked microsatellite markers that will be useful for the positional cloning of tlt.
Asunto(s)
Ratones Mutantes/genética , Membrana Otolítica/anomalías , Mapeo Físico de Cromosoma/métodos , Proteínas Tirosina Quinasas , Animales , Centrómero , Cruzamientos Genéticos , Marcadores Genéticos , Proteína Huntingtina , Meiosis , Ratones , Ratones Endogámicos , Proteínas del Tejido Nervioso/genética , Proteínas Nucleares/genética , Reacción en Cadena de la Polimerasa , Receptor Tipo 3 de Factor de Crecimiento de Fibroblastos , Receptores de Factores de Crecimiento de Fibroblastos/genética , Natación/fisiologíaRESUMEN
The mouse TNFR2 gene has been cloned, sequenced, and characterized as a gene spanning >44 kb of the genome. By alignment of five genomic clones we have established that TNFR2 consists of 10 exons and 9 introns with exons ranging in size from 35 bp to 2.6 kb and introns ranging from 322 bp to >16 kb. All splice acceptor and donor sites conform to the canonical AG/GT rule. The translation initiation and termination sites are located in exon 1 and 10, respectively. Although TNFR2 lacks a canonical TATA box, the gene is transcribed from a unique start site located 70 bp upstream of the ATG initiation codon that conforms to the consensus Inr motif. Several cis-elements for transcription factors were identified in the 5' flanking region, including NF-1, Sp-1, AP2, gamma-IRE, and NF-kappaBeta motifs. Functional analysis indicates that the region -705/-412 contains a negative cis-acting element and that the minimal promoter contains motifs that confer LPS inducibility. Two mouse TNFR2 mRNAs of 3.2 and 4.1 kb are detected by Northern blot analysis, but until now their origin has not been explained. No evidence of alternative splicing of the coding exons was found. However, hybridization studies and amplification of cDNA ends suggest the use of a noncanonical polyadenylation signal in the untranslated region of exon 10. A comparative analysis of the 3' untranslated regions of the human and mouse TNFR2 genes shows highly divergent 3' ends. The possibility of an ancestral mouse TNFR2 mRNA similar to the short transcript is discussed.
Asunto(s)
Antígenos CD/química , Antígenos CD/genética , Receptores del Factor de Necrosis Tumoral/química , Receptores del Factor de Necrosis Tumoral/genética , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Clonación Molecular , Codón Iniciador/genética , Humanos , Ratones , Datos de Secuencia Molecular , Mutagénesis Sitio-Dirigida , Regiones Promotoras Genéticas/genética , Receptores Tipo II del Factor de Necrosis Tumoral , Análisis de Secuencia de ADN , Eliminación de Secuencia , Transcripción GenéticaRESUMEN
We report the identification of a mouse cDNA, SIG41, encoding a protein of 288 amino acids that is 45% identical (58% similar) to the Drosophila splicing regulator Tra2. SIG41 cDNA contains four polyadenylation signals whose alternative use gives rise to four types of transcripts (2.1, 2.0, 1.5, and 1.4 kb) in mouse cells. Northern analysis and RT-PCR assays showed that SIG41 mRNA is present in virtually all the cell lines and tissues studied, with remarkable levels of expression in uterus and brain tissues. Differential stability of the SIG41 mRNAs was detected in mouse macrophage cells.
Asunto(s)
Proteínas de Drosophila , Empalme del ARN , Proteínas de Unión al ARN/genética , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Línea Celular , Clonación Molecular , Cartilla de ADN , ADN Complementario , Drosophila melanogaster/metabolismo , Expresión Génica , Ratones , Datos de Secuencia Molecular , Proteínas Nucleares , ARN Mensajero , Proteínas de Unión al ARN/química , Proteínas de Unión al ARN/metabolismo , Ribonucleoproteínas/química , Ribonucleoproteínas/genética , Homología de Secuencia de Aminoácido , Factores de Empalme Serina-ArgininaRESUMEN
We report the cloning, nucleotide sequence, evolutionary analysis, and intracellular localization of SIG81, a silica-induced cDNA from mouse macrophages. The cDNA encodes a 111-amino acid protein with extensive sequence identity with members of the mammalian cytochrome c oxidase subunit VIIa (COX7a) family. A human SIG81 sequence >80% identical with the mouse cDNA was deducted from homologous sequences in the human expressed tags data base. The deduced aminoterminal region shows features common to mitochondrial targeting sequences. A phylogenetic analysis of the carboxyl-terminal domain homologous to COX7a identifies SIG81 as a divergent member of the family with an ancient origin. Southern blot analysis showed that the mouse genome contains two to three copies of the SIG81 gene. Northern blot analysis revealed that the SIG81 transcript is approximately 1 kb and expressed in every tissue tested, with higher levels of expression observed in kidney and liver. Antibodies raised against a glutathione S-transferase SIG81 fusion protein detected a 13.5-kDa protein that co-fractionates with mitochondrial localized enzymatic activity. Taken together, our data suggest that SIG81 is a novel member of the COX7a family that is constitutively expressed in mouse cells.
Asunto(s)
Complejo IV de Transporte de Electrones/genética , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Clonación Molecular , ADN Complementario , Complejo IV de Transporte de Electrones/metabolismo , Humanos , Ratones , Datos de Secuencia Molecular , Filogenia , ARN Mensajero/genética , Homología de Secuencia de Aminoácido , Fracciones Subcelulares/enzimologíaRESUMEN
In mouse RAW 264.7 macrophages, the gene for ribosomal protein L26 is positively regulated by silica. In order to study L26 gene expression a near full-length cDNA for mouse L26 was isolated and characterized. Sequence analysis revealed that mouse L26 is a 145 amino acid protein highly homologous to other vertebrate L26 proteins. The treatment of RAW 264.7 cells with the inflammatory mediators LPS and IFN gamma induced the expression of L26 mRNA, but the patterns of expression obtained differed markedly from silica. On the contrary, TNF alpha acted as a down-regulator of L26 gene. Our results suggest that the synthesis of ribosomal components in response to macrophage activators is inducer-specific. Mouse genomic DNA analysis revealed the presence of multiple (10-12) sequences related to the L26 gene.
