Histone mRNA Regulation in Development

描述(申请人提供)：依赖动物复制的组蛋白mRNAs是唯一没有Polya尾巴而以保守的茎环结尾的真核mRNAs。相反，组蛋白变体的mRNAs，例如H3.3和H2.v，是由多腺化的mRNAs编码的。所有五种组蛋白的基因都聚集在后生动物基因组中，组蛋白基因表达所需的因子位于组蛋白基因附近。我们将以果蝇为模型系统，确定复制依赖的组蛋白mRNAs在体内协同表达的要求，特别是组蛋白基因体在组蛋白mRNA代谢中的作用。我们将使用生物化学和遗传学的方法来确定：1.有效地生产正确加工的组蛋白mRNA所需的组蛋白组分Flash和NPAT的结构要求；2.组蛋白基因位点上决定组蛋白基因座形成组蛋白的序列；3.组蛋白切割因子的组成，包括多聚腺苷酸化因子Symplekin、CPSF73和CPSF100，并阐明Symplekin在组蛋白前mRNA体外和体内加工中的作用。

DESCRIPTION (provided by applicant): Animal replication-dependent histone mRNAs are the only eukaryotic mRNAs that lack a polyA tail ending instead in a conserved stemloop. In contrast mRNAs for histone variants, e.g. H3.3 and H2.v, are encoded by polyadenylated mRNAs. The genes for all five histone proteins are clustered in metazoan genomes, and factors required for histone gene expression are localized near the histone genes. We will determine the requirements for the coordinate expression of the replication-dependent histone mRNAs in vivo using Drosophila as a model system, and in particular the role of the Histone Locus Body in histone mRNA metabolism. We will use both biochemical and genetic approaches to determine 1. The structural requirements in the HLB components FLASH and NPAT required for efficient production of properly processed histone mRNA, 2. The sequences in the histone gene locus that specifies the formation of the HLB at the histone locus and 3. The composition of the histone cleavage factor, which contains polyadenylation factors Symplekin, CPSF73 and CPSF100, will be determined and the role of Symplekin in histone pre-mRNA processing in vitro and in vivo elucidated.