GENE TRANSCRIPTION IN DROSOPHILA

我们发现hnRNA组装成核糖核蛋白 在果蝇的热休克过程中颗粒被阻断。 我们建议， 这种情况有利于mRNA的加工，其核成熟是 独立于RNP结构。 这一假设将在各种测试中得到验证。 的基因系统，特别强调核RNP结构， 内含子缺失基因的mRNA转录本。 hnRNP的热休克阻断 组装也将进一步研究。 我们已经确定了具体的 在果蝇中与小核RNA U1结合的蛋白质， 一种新的研究小核RNP的方法， 组装件. 我们现在建议鉴定这些果蝇snRNP蛋白 独特的U1 RNP，以确定这些蛋白质的位置在U1 RNA的， 体外组装和核酸酶探针，将U1 RNP结构与溶液相关联 果蝇U1 RNA的二级结构 类似的研究将在 果蝇U4 RNA和RNP。 主要U1 RNP蛋白的mRNA将 克隆并用于研究这些mRNA的转录及其 与哺乳动物snRNP蛋白mRNA的核苷酸序列同源性， 已经在不同的项目中进行了克隆。 小核RNA U1被认为是 参与mRNa剪接，但现有证据表明， 引人注目。 我们已经使用peptide交联来确定U1 RNA是 在体内与hnRNA碱基配对。 我们现在将检查U1碱基配对， 特定的果蝇核RNA转录本， 内含子

We have discovered that the assembly of hnRNA into ribonucleoprotein particles is blocked during heat shock in Drosophila. We propose that this situation favors the processing of mRNA's whose nuclear maturation is independent of RNP structure. This hypothesis will be tested in a variety of gene systems, with particular emphasis on the nuclear RNP structure of mRNA transcripts of intron-lacking genes. The heat shock block of hnRNP assembly will also be further investigated. We have identified specific proteins bound to small nuclear RNA U1 in Drosophila and have developed a novel approach for studying small nuclear RNP's based on in vitro assembly. We now propose to identify those Drosophila snRNP proteins unique to U1 RNP, to locate the positions of these proteins on U1 RNA by in vitro assembly and nuclease probes, relate U1 RNP structure to the solution secondary structure of Drosphila U1 RNA. Similar studies will be done for Drosophila U4 RNA and RNP. The mRNA's for the major U1 RNP proteins will be cloned and used to study the transcription of these mRNA's and their nucleotide sequence homology with mammalian snRNP protein mRNA's that we are already cloning in separate projects. Small nuclear RNA U1 is thought to be involved in mRNa splicing, but the available evidence is not compelling. We have used psoralen crosslinking to establish that U1 RNA is based-paired with hnRNA in vivo. We will now examine U1 base-pairing in specific Drosophila nuclear RNA transcripts that either contain or lack introns.