芽殖酵母细胞周期过程不同时期的定量观测

在芽殖酵母中构建CDC10-mCherry和SPC42-mCherry荧光蛋白, 作为酵母细胞周期不同时期的报告系统。根据酵母细胞中芽环(CDC10-mCherry)的产生和消失以及纺锤体极体(SPC42-mCherry)的复制和分离,可以测量细胞周期中 G1期、S期、Early M期和Late M期的时间长度。在此报告系统的基础上, 分别构建S期细胞周期蛋白CLB5-GFP和M 期细胞周期蛋白CLB2-GFP菌株, 实现单细胞观测, 检验报告系统工作的稳定性和准确性。该报告系统可作为研究酵母细胞周期不同时期时间长度等定量生物学问题的背景菌株。     

Sequential activation of HOX2 homeobox genes by retinoic acid in human embryonal carcinoma cells

RETINOIC acid had been implicated as a natural morphogen in chicken and frog embryogenesis, and is presumed to act through the gene regulatory activity of a family of nuclear receptors. Homeobox genes, which specify positional information in Drosophila and possibly in vertebrate embryogenesis, are among the candidate responsive genes. We previously reported that retinoic acid specifically induces human homeobox gene (HOX) expression in the embryonal carcinoma cell line NT2/D1. We now show that the nine genes of the HOX2 cluster are differentially activated in NT2/D1 cells exposed to retinoic acid concentrations ranging from 10(-8) to 10(-5) M. Genes located in the 3' half of the cluster are induced at peak levels by 10(-8) M retinoic acid, whereas a concentration of 10(-6) to 10(-5) M is required to fully activate 5' genes. At both high and low retinoic acid concentrations, HOX2 genes are sequentially activated in embryonal carcinoma cells in the 3' to 5' direction.     

A relationship between the yeast cell cycle genes CDC4 and CDC36 and the ets sequence of oncogenic virus E26

We report here significant primary sequence homology among the predicted translational products of three genes: CDC4 , CDC36 and ets. CDC4 and CDC36 are Saccharomyces cerevisiae cell division cycle genes, while ets is a transformation-specific sequence of avian erythroblastosis virus E26. The deduced primary structures of the three gene products were compared by computer to a large data base of known and predicted protein sequences. The search revealed 22.0-25.5% identity over regions of 140-206 codons, respectively between the different pairwise combinations. For these particular sequences, these identity scores fall 3.4-4.0 standard deviations above the empirically-determined mean values of fortuitous similarity. S. cerevisiae calls require CDC36 and CDC4 in order to complete two early events in the cell cycle: execution of start ( CDC36 ) and spindle pole body separation ( CDC4 ). In virus E26, the ets sequence is linked in frame with delta gag and mybE in the tripartite structure 5'-delta gag- mybE -ets-3', comprising the E26 transforming oncogene. The homologies described here suggest that the biochemical functions or regulation of the CDC4 , CDC36 and ets products may be related.     

miR-1/133基因簇的进化及其调控网络

miR-1/133基因簇在心肌和骨骼肌中特异性表达,对心脏以及骨骼肌的发育及生理病理具有重要作用.该研究采用生物信息学方法,研究了miR-1/133基因簇的进化特征,预测了其靶基因及其调控的生物学过程.利用miRBase数据库对23种不同物种间miR-1/133基因簇的序列、组织方式进行了比较.采用最大似然法构建miR-1/133基因簇的系统进化树,显示该基因簇的进化与物种进化关系有一定差异.利用在线数据库对miR-1/133基因簇上游转录因子及下游靶基因进行预测,并对其进行综合分析,绘制出该基因簇的网络调控图,表明miR-1/133基因簇参与了骨骼肌与心肌发育、胰岛素受体信号通路、经典Wnt信号通路、p53信号通路等体内重要生理过程,为进一步阐明miR-1/133基因簇的生物学功能提供了理论依据.