Prediction of the Coding Sequences of Unidentified Human Genes. III. The Coding Sequences of 40 New Genes (KIAA0081-KIAA0120) Deduced by Analysis of cDNA Clones from Human Cell Line KG-1

We isolated full-length cDNA clones from size-fractionated cDNAlibraries of human immature myeloid cell line KG-1, and thecoding sequences of 40 genes were newly predicted. A computersearch of the GenBank/EMBL databases indicated that the sequencesof 14 genes were unrelated to any reported genes, while theremaining 26 genes carried some sequences with similaritiesto known genes. Significant transmembrane domains were identifiedin 17 genes, and protein motifs that matched those in the PROSITEmotif database were identified in 11 genes. Northern hybridizationanalysis with 18 different cells and tissues demonstrated that10 genes were apparently expressed in a cell-specific or tissue-specificmanner. Among the genes predicted, half were isolated from themedium-sized cDNA library and the other half from the small-sizedcDNA library, and their average sizes were 4 kb and 1.4 kb,respectively. As judged by Northern hybridization profiles,small-sized cDNAs appeared to be expressed more ubiquitouslyand abundantly in various tissues, compared with that of medium-sizedcDNAs.     

Prediction of the Coding Sequences of Unidentified Human Genes. IV. The Coding Sequences of 40 New Genes (KIAA0121-KIAA0160) Deduced by Analysis of cDNA Clones from Human Cell Line KG-1

In this series of projects regarding the accumulation of sequenceinformation of unidentified human genes, we newly deduced thesequences of 40 full-length cDNA clones of human cell line KG-1,and predicted the coding sequences of the corresponding genes,named KIAA0121 to 0160. The results of a computer search ofpublic databases indicated that the sequences of 13 genes wereunrelated to any reported genes, while the remaining 27 genescarried sequences which showed some similarities to known genes.Obvious unique sequences noted were as follows. A stretch oftriplet repeats was contained in each of three genes: Thesewere GAG(Glu) in KIAA0122 and KIAA0147, and TCC(Ser) in KIAA0150.A stretch of 10 amino acidresidues was repeated 21 times inKIAA0139, and a homologous sequence of 76–78 nucleotideswas found repeated 6 times in the untranslated region of KIAA0125.northern hybridization analysis demonstrated that 13 genes wereexpressed in a cell- or tissue-specific manner. Although a vastnumber of expressed sequence tags (ESTs) have been registeredfor comprehensive analysis of cDNA clones, our sequence dataindicated that their distribution is very unbalanced: e.g. whileno EST hit 7 genes, 85 ESTs fell in a single gene.     

Clustering of Genes Coding for DNA Binding Proteins in a Regionof Atypical Evolution of the Human Genome

Comparison of the human and mouse genomes has revealed that significant variations in evolutionary rates exist among genomic regions and that a large part of this variation is interchromosomal. We confirm in this work, using a large collection of introns, that human chromosome 19 is the one that shows the highest divergence with respect to mouse. To search for other differences among chromosomes, we examine the distribution of gene functions in human and mouse chromosomes using the Gene Ontology definitions. We found by correspondence analysis that among the strongest clusterings of gene functions in human chromosomes is a group of genes coding for DNA binding proteins in chromosome 19. Interestingly, chromosome 19 also has a very high GC content, a feature that has been proposed to promote an opening of the chromatin, thereby facilitating binding of proteins to the DNA helix. In the mouse genome, however, a similar aggregation of genes coding for DNA binding proteins and high GC content cannot be found. This suggests that the distribution of genes coding for DNA binding proteins and the variations of the chromatin accessibility to these proteins are different in the human and mouse genomes. It is likely that the overall high synonymous and intron rates in chromosome 19 are a by-product of the high GC content of this chromosome.Department of Physiology and Molecular Biodiversity, Institut de Biologia Molecular de Barcelona, CSIC, Jordi Girona 18, 08034 Barcelona, Spain     

粳稻和籼稻D1蛋白光抑制敏感性的差异与其编码基因序列结构特征的相关性分析(英文)

粳稻 (OryzasativaL .ssp .japonica)和籼稻 (O .sativassp .indica)对光抑制的敏感程度存在差异 ,它们的叶绿体光反应中心Ⅱ核心蛋白D1的稳定性不同。以菌落原位杂交法克隆了粳稻“95 16”和籼稻“籼优 6 3”叶绿体D1蛋白的编码基因psbA。核苷酸序列同源比较显示 :两者在启动子区和 5′_UTR完全相同 ;编码区存在着个别碱基的差异 ,但均位于三联体密码的第三位 ,不影响氨基酸编码特性 ,在蛋白质氨基酸序列上没有差异 ;在 3′_UTR内存在寡聚U长度的差异。因此 ,粳稻和籼稻D1蛋白对光抑制作用敏感性的差异与其蛋白质的氨基酸序列结构无关 ,可能与调控psbA基因表达的上游因子或光保护机制的差异有关。     

A Micromethod for the Isolation of Large and Small Microvessels from Frozen Autopsied Human Brain

Microvessels were isolated from autopsied human brain using a simple procedure involving disruption, sieving, and centrifugation on a sucrose density gradient. The present procedure is characterized by isolation, from frozen autopsied brain, of materials either from the cerebral cortex or white matter, and subsequent separation of the capillary fraction from the large vessel fraction. The preparation appears highly purified under phase-contrast microscopic examination. The purity was also established by the enrichment of gamma-glutamyl transpeptidase activity and by the nearly negligible cerebroside content in the vessel fractions as compared to the brain homogenate.