Histone mRNA Regulation in Development

描述（由申请人提供）：动物复制依赖性组蛋白mrna是真核生物中唯一缺乏polyA尾端而不是保守茎环的mrna。相反，组蛋白变体的mrna，例如H3.3和H2。v，由聚腺苷化mrna编码。这五种组蛋白的基因都聚集在后生动物的基因组中，而组蛋白基因表达所需的因子则定位在组蛋白基因附近。我们将以果蝇为模型系统，确定复制依赖性组蛋白mRNA在体内协调表达的要求，特别是组蛋白位点体在组蛋白mRNA代谢中的作用。我们将使用生物化学和遗传方法来确定1。HLB组分FLASH和NPAT的结构要求是有效生产适当加工的组蛋白mRNA所必需的，2。组蛋白基因座中指定组蛋白位点和3处HLB形成的序列。组蛋白切割因子包括多腺苷化因子Symplekin、CPSF73和CPSF100，其组成将被确定，并在体外和体内阐明Symplekin在组蛋白pre-mRNA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.