RESUMO
Reelin is an extracellular matrix protein that is defective in reeler mutant mice and plays a key role in the organization of architectonic patterns, particularly in the cerebral cortex. In mammals, a "reelin signal" is activated when reelin, secreted by Cajal-Retzius neurons, binds to receptors of the lipoprotein receptor family on the surface of cortical plate cells, and triggers Dab1 phosphorylation. As reelin is a key component of cortical development in mammals, comparative embryological studies of reelin expression were carried out during cortical development in non-mammalian amniotes (turtles, squamates, birds and crocodiles) in order to assess the putative role of reelin during cortical evolution. The data show that reelin is present in the cortical marginal zone in all amniotes, and suggest that reelin has been implicated in the evolution of the radial organization of the cortical plate in the synapsid lineage leading from stem amniotes to mammals, as well as in the lineage leading to squamates, thus providing an example of homoplastic evolution (evolutionary convergence). The mechanisms by which reelin instructs radial cortical organization in these two lineages seem different: in the synapsid lineage, a drastic amplification of reelin production occurred in Cajal-Retzius cells, whereas in squamates, in addition to reelin-secreting cells in the marginal zone, a second layer of reelin-producing cells developed in the subcortex. Altogether, our results suggest that the reelin-signaling pathway has played a significant role in shaping the evolution of cortical development
Assuntos
Animais , Evolução Biológica , Córtex Cerebral , Proteínas da Matriz Extracelular , Transdução de Sinais , Córtex Cerebral , Proteínas Fúngicas , Modelos Neurológicos , Moléculas de Adesão de Célula Nervosa , RNA MensageiroRESUMO
Hereditary neuralgic amyotrophy (HNA) is an autosomal dominant recurrent neuropathy mapped to a 4-cM interval on chromosome 17q25 between the short tandem repeat (STR) markers D17S1603 and D17S802. Chromosome 17q25 in general and the 4-cM HNA region in particular are also implicated in the pathogenesis of a number of tumors (tylosis with esophageal cancer, sporadic breast and ovarian tumors) and harbor a psoriasis susceptibility locus. Initial attempts to construct a yeast artificial chromosome contig failed. Therefore, we have now constructed a complete P1 artificial chromosome (PAC) and bacterial artificial chromosome (BAC) contig of the region flanked by the STR markers D17S1603 and D17S802. The contig contains 22 PAC and 64 BAC clones and covers a physical distance of approximately 1. 5 Mb. A total of 83 sequence-tagged site (STS) markers (10 known STSs and STRs, 56 STSs generated from clone end-fragments, 12 expressed sequence tags, and 5 known genes) were mapped on the contig, resulting in an extremely dense physical map with approximately 1 STS per 20 kb. This sequence-ready PAC and BAC contig will be pivotal for the positional cloning of the HNA gene as well as other disease genes mapping to this region.
Assuntos
Bacteriófago P1/genética , Cromossomos Bacterianos/genética , Cromossomos Humanos Par 17/genética , Genes , Transcrição Gênica , Neurite do Plexo Braquial/genética , Cromossomos Artificiais de Levedura/genética , Clonagem Molecular , Mapeamento de Sequências Contíguas/métodos , Etiquetas de Sequências Expressas , Humanos , Neoplasias/genética , Psoríase/genética , Sitios de Sequências RotuladasRESUMO
The rat Chromosome (Chr) 2 harbors several genes controlling tumor growth or development, blood pressure, and non-insulin-dependent diabetes mellitus. We report that the region (2q1) containing the mammary susceptibility cancer gene Mcs1 also harbors the genes encoding cyclin B1, interleukin 6 signal transducer (gp130), and proprotein convertase 1. We also generated 13 new anonymous microsatellite markers from Chr 2-sorted DNA. These markers, as well as a microsatellite marker in the cyclin B1 gene, were genetically mapped in combination with known markers. A cyclin B1-related gene was also cytogenetically assigned to rat Chr 11q22-q23.
Assuntos
Antígenos CD/genética , Ciclina B/genética , Glicoproteínas de Membrana/genética , Repetições de Microssatélites , Pró-Proteína Convertases , Proteínas de Saccharomyces cerevisiae , Subtilisinas/genética , Animais , Mapeamento Cromossômico , Ciclina B1 , Receptor gp130 de Citocina , Ligação Genética , Hibridização in Situ Fluorescente , RatosRESUMO
Seven genes were regionally localized on rat Chromosome (Chr) 1, from 1p11 to 1q42, and two of these genes were also included in a linkage map. This mapping work integrates the genetic linkage map and the cytogenetic map, and allows us to orient the linkage map with respect to the centromere, and to deduce the approximate position of the centromere in the linkage map. These mapping data also indicate that the Slc9a3 gene, encoding the Na+/H+ exchanger 3, is an unlikely candidate for the blood pressure loci assigned to rat Chr 1. These new localizations expand comparative mapping between rat Chr 1 and mouse or human chromosomes.
Assuntos
Mapeamento Cromossômico/métodos , Cromossomos , Ligação Genética , Proteínas Proto-Oncogênicas , Animais , Pressão Sanguínea/genética , Centrômero/genética , Chaperonina com TCP-1 , Chaperoninas/genética , Colestenona 5 alfa-Redutase , Humanos , Hibridização in Situ Fluorescente , Janus Quinase 2 , Ácido Caínico/metabolismo , Camundongos , Oxirredutases/genética , Proteínas Tirosina Quinases/genética , Ratos , Ratos Endogâmicos Lew , Ratos Endogâmicos SHR , Receptores de Estradiol/genética , Receptores de Glutamato/genética , Receptores de Glutamato/metabolismo , Trocadores de Sódio-Hidrogênio/genética , Troponina/genéticaRESUMO
Using fluorescence in situ hybridization, we determined that the three rat PAP genes, and the related REG gene map in the same chromosomes region, namely 4q33-->q34. This rat chromosome region is thus homologous to the human 2p12 region, which also contains the PAP gene, the REG1A gene, and a REG-related gene (REGL).
Assuntos
Proteínas de Fase Aguda/genética , Antígenos de Neoplasias , Biomarcadores Tumorais , Proteínas de Ligação ao Cálcio/genética , Lectinas Tipo C , Proteínas do Tecido Nervoso , Ratos/genética , Animais , Mapeamento Cromossômico , Hibridização in Situ Fluorescente , Litostatina , Proteínas Associadas a PancreatiteRESUMO
By means of somatic cell hybrids segregating rat chromosomes, we determined the chromosome localization of three rat genes of the Jun family: Junb (Chr 19), Jun (=c-Jun) (Chr 5) and Jund (Chr 16). The Jun gene was also localized to the 5q31-33 region by fluorescence in situ hybridization. These rat gene assignments reveal two new homologies with mouse and human chromosomes, and provide a new example of synteny conserved in the human and a rodent species (the mouse), but split between the two rodent species.