Cytogenetics and cell genetics最新文献

The processed product of the human gene preprocortistatin, the peptide cortistatin-17 (hCST-17), bears a strong structural resemblance to the peptide somatostatin (SST), which has an identical receptor binding domain. CST has affinity to all known SST receptor (SSTR) subtypes. Expression of both SST and its receptors has been shown in previous studies to have biological and clinical significance in neuroblastomas, with a putative role in tumor differentiation and apoptosis in vivo. In this work we have employed radiation hybrid mapping and BAC physical mapping to map the human preprocortistatin gene (CORT) to chromosome region 1p36.3-->p36.2, close to the genetic marker D1S244. D1S244 defines the centromeric border of the smallest region of overlap of deletion in our primary neuroblastoma material. We have also defined the genomic sequence of the gene by BAC sequencing and found that preprocortistatin consists of two exons divided by a 1-kb intron. Two polymorphic sites, neither of which causes amino acid exchange, have been detected in the coding region of the gene. Expression studies showed that preprocortistatin is expressed in neuroblastomas of all different stages, as well as in ganglioneuromas. Through genomic sequencing we made mutation analyses of exonic sequences in 49 primary neuroblastomas of all different stages, but no mutations could be detected.

Based on its Z-sex-chromosomal location and its structural homology to male sexual regulatory factors in humans (DMRT1 and DMRT2), Drosophila (Dsx), and Caenorhabditis elegans (Mab-3), chicken DMRT1 is an excellent candidate for a testis-determining factor in birds. The data we present provide further strong support for this hypothesis. By whole mount in situ hybridization chicken DMRT1 is expressed at higher levels in the male than in the female genital ridges during early stages of embryogenesis. Its expression becomes testis-specific after onset of sexual differentiation. Northern blot and RT PCR analysis showed that in adult birds DMRT1 is expressed exclusively in the testis. We propose that two gene dosages are required for testis formation in ZZ males, whereas expression from a single Z chromosome in ZW females leads to female sexual differentiation.

The integrin family of receptors serves as major receptors for extracellular matrix-mediated cell adhesion and migration, cytoskeletal organisation, cell proliferation, survival, and differentiation. The alpha-V integrins consist of a subset which share a common alpha-V subunit combined with one of five beta subunits (beta-1, 3, 5, 6, or 8). The alpha-V integrins have been implicated in a number of developmental processes, including vasculogenesis and angiogenesis, and are therapeutic targets for inhibition of angiogenesis and osteoporosis. The human cDNA for alpha-V integrin (ITGAV) consists of a 5,717-bp transcript with a coding sequence (CDS) of 3,146 bp encoding a 150-kDa mature peptide. Here we describe the gene structure of ITGAV.

SALL1 has been identified as one of now three human homologs of the region specific homeotic gene spalt (sal) of Drosophila, which encodes a zinc finger protein of characteristic structure. Mutations of SALL1 on chromosome 16q12.1 cause Townes-Brocks syndrome (TBS, OMIM no. 107480). In order to facilitate functional studies of this gene in a model organism, we searched for the murine homolog of SALL1. Here we report the genomic cloning, chromosome mapping, and partial expression analysis of the gene Sall1. Sequence comparison, Northern blot hybridization as well as the conserved chromosome location on the homologous mouse chromosome indicate that we have indeed isolated the murine homolog of SALL1.

Holoprosencephaly (HPE) is the most common developmental defect of the brain and face in humans. Here we report the analysis of the human ortholog of dkk-1 as a candidate gene for HPE. We determined the genomic structure of the human gene DKK1 and mapped it to chromosome 10q11.2. Functional analysis of four missense mutations identified in HPE patients revealed preserved activity in head induction assays in frogs suggesting a limited role for this gene in HPE pathogenesis.

The mouse glucocorticoid-induced receptor (GIR) is an orphan G protein-coupled receptor highly expressed in brain and thymus (Harrigan et al., 1989; 1991). We have cloned the mouse GIR gene (Gpr83), determined its genomic organization and compared it with the human gene. The genomic organization of the gene is similar in both species although differences leading to specific splicing variants in the mouse have been found. Three introns interrupting the coding sequence are common to both mouse and human. A short sequence in the second intron of the mouse gene can be alternatively spliced in, leading to an insertion in the second intracellular loop of the receptor. This insertion constitutes an additional exon which is not present in the human genome. The human GIR polypeptide shares 89.5% and 91.5% identity with its mouse and dog orthologs respectively. Splice variants lacking the first extracellular loop and the third transmembrane domain have been found in human and mouse species. The receptor variants resulting from these minor transcripts are likely to be non functional. Comparative genetic mapping of the Gpr83 gene showed that it maps to regions of conserved synteny on mouse chromosome 9 (A2-3 region) and human chromosome 11 (q21 region).