转录因子与microRNA在基因表达调控中的功能联系及差异

转录因子和微RNA(microRNA)是最大的两类反式作用因子,它们是基因表达调控的重要调控因子.它们协调发挥调控作用,精细调控基因的表达,在细胞分化和动物生长发育过程中发挥重要的作用.随着对转录因子和microRNA研究的深入,人们发现转录因子和microRNA在基因表达调控网络中关系紧密,它们的分子作用机制有许多相似之处,两者都通过各自的顺式作用元件调控基因表达,且作用的方式类似.但转录因子和microRNA也存在不同之处,转录因子既可以激活基因表达,也可抑制基因表达,而microRNA主要是抑制基因表达.另外,转录因子调控区的复杂性一般高于microRNA的调控区域.本文综述了转录因子和microRNA的异同点,并提出了未来转录因子和microRNA的研究方向.     

A complex 'mRNA degradation code' controls gene expression during animal development

Current understanding of the molecular mechanisms underlying mRNA degradation indicates that specific mRNA degradation rates are primarily encoded within the mRNA message itself in the form of cis-regulatory elements bearing particular primary sequences and/or secondary-structures. Such control elements are operated by RNA-binding proteins (RBPs) and/or miRNA-containing complexes. Based on the large number of RBPs and miRNAs encoded in metazoan genomes, their complex developmental expression and that specific RBP and miRNA interactions with mRNAs can lead to distinct degradation rates, I propose that developmental gene expression is shaped by a complex 'mRNA degradation code' with high information capacity. Localised cellular events involving the modification of RBP and/or miRNA target sequences in mRNAs by alternative polyadenylation added to the activation of specific RBP and miRNA activities via cell signalling are predicted to further expand the capacity of the mRNA degradation code by coupling it to dynamic events experienced by cells at specific spatiotemporal coordinates within the developing embryo.