Cytogenetics and cell genetics最新文献

We describe the complete sequence, genomic organization, and FISH chromosome mapping of the human VAMP2. We identified a 7-kb clone, pISSHG2b3A, containing the entire structure of VAMP2. Previous studies performed by others identified a 5-kb clone, pVPC5-2, containing the incomplete VAMP2. The pVPC5-2 clone was partially sequenced and mapped to the broad region 17pter-->p12 by somatic cell hybridization. Our clone overlaps the pVPC5-2 clone and extends approximately 2 kb at the 3' end. In this study, we mapped this gene more precisely on 17p12 by FISH and we found a new polymorphic microsatellite, (GT)(7)CC(GT)(5), in exon V. This microsatellite, revealing three alleles with frequencies of 0.778, 0.139, and 0.083, might be useful for future linkage studies. Finally, we localized three previously known markers, stSG12859, TIGR-A002F11, and WIAF-1699 (alias stSG4044), in the 3' untranslated region of the gene.

The murine Na(+)/myo-inositol cotransporter (SLC5A3) gene (Slc5a3) was cloned, the restriction sites mapped, and the coding region sequenced. Similar to other mammalian counterparts, including human, the gene has a single coding exon, with an open reading frame of 2.2 kb. The predicted protein of 718 amino acids is also highly conserved, compared to other mammalian homologs. Using fluorescence in situ hybridization, Slc5a3 was localized to the telomeric region of mouse chromosome 16, which is syntenic to human chromosome 21q22. An increased Slc5a3 copy number may explain the increased levels of myo-inositol in the brains of trisomy 16 mice and the increased rate of transport of myo-inositol into cultured neurons derived from trisomy 16 mice.

We have used data from chromosomally unbalanced offspring observed at birth, as well as data from sperm chromosome analysis, to study the meiotic segregation of reciprocal translocations. Using data from a total of 1,597 unbalanced children, we have observed an excess in maternal origin for all modes of imbalance. This excess is particularly marked for the 3:1 unbalanced mode, for which we have also observed a maternal age effect, indicating a close relationship with autosomal trisomies. In addition, a statistical analysis of data from 34 different published studies using sperm chromosome analysis has demonstrated that factors which, for reasons of viability, produce a predisposition for a particular mode of imbalance at birth also appear to favor meiotic production of this type of imbalance. Thus the production of unbalanced gametes of a particular type is influenced by the size of the imbalance.

A family of negative regulators of JAK signaling pathway referred to as suppressor of cytokines signaling (SOCS) or cytokine-inducible SH2 protein (CIS) has been recently identified. In order to find additional members of this family, we have used a consensus amino acid sequence contained in the well-conserved central SH2 domain to search DNA databases. We isolated cDNA coding for the human homologue of SOCS-5, referred to as CIS6. Northern blot analysis revealed CIS6 mRNA expression in various tissues such as heart, muscle, spleen, and thymus and in all myeloma cell lines examined. The gene was assigned to human chromosome bands 2p21 and 3p22 by in situ hybridization. CIS6 is structurally related to other members of the CIS family and therefore could act as a negative regulator of signal transduction.

A key feature of interphase chromosomes is their compaction into discrete "territories" in the nucleus. In this review, we focus on the compartmentalization of the genome conferred by this organization and evaluate our current understanding of the role of large-scale chromatin folding in the regulation of gene expression. We examine evidence for the hypothesis that transcription occurs at the external surfaces of chromosomes and follow its evolution to include transcription at the surfaces of chromatin-rich domains within chromosomes. We also present prevailing views regarding the details of large-scale chromatin folding and the functional relationship between chromatin and the enigmatic nuclear matrix.

Rat acetyl-CoA transporter gene (Acatn) encodes a hydrophobic multi-transmembrane protein involved in the O-acetylation of gangliosides. O-acetylated gangliosides have been found to play important roles in the embryonic development of the nervous system. We have isolated rat Acatn cDNA by PCR cloning. The amino acid sequence of rat Acatn exhibited 92% and 96% homology with human and mouse sequences, respectively. The mRNA was expressed in brain at all developmental stages. Acatn expression was higher in embryonic and postnatal rats than in adult rats. Cellular localization of Acatn mRNA in adult rat brain was also analyzed by in situ hybridization. Acatn mRNA expression was detected in the neuronal cells of cerebellum, hippocampus, hypothalamus, cortex, olfactory bulb, and dorsal and ventral anterior olfactory nucleus in adult rat brain.

By fluorescence in situ hybridization (FISH) using mouse probes, we assigned homologues for cathepsin E (Ctse), protocadherin 10 (Pcdh10, alias OL-protocadherin, Ol-pc), protocadherin 13 (Pcdh13, alias protocadherin 2c, Pcdh2c), neuroglycan C (Cspg5) and myosin X (Myo10) genes to rat chromosomes (RNO) 13q13, 2q24-->q25, 18p12-->p11, 8q32.1 and 2q22.1-->q22.3, respectively. Similarly, homologues for mouse Ctse, Pcdh13, Cspg5 and Myo10 genes and homologues for rat Smad2 (Madh2) and Smad4 (Madh4) genes were assigned to Chinese hamster chromosomes (CGR) 5q28, 2q17, 4q26, 2p29-->p27, 2q112-->q113 and 2q112-->q113, respectively. The chromosome assignments of homologues of Ctse and Cspg5 reinforced well-known homologous relationships among mouse chromosome (MMU) 1, RNO 13 and CGR 5q, and among MMU 9, RNO 8 and CGR 4q, respectively. The chromosome locations of homologues for Madh2, Madh4 and Pcdh13 genes suggested that inversion events were involved in chromosomal rearrangements in the differentiation of MMU 18 and RNO 18, whereas most of MMU 18 is conserved as a continuous segment in CGR 2q. Furthermore, the mapping result of Myo10 and homologues suggested an orthologous segment of MMU 15, RNO 2 and CGR 2.