CHROMATIN STRUCTURE AND GENE REGULATION OF ROSY LOCUS

染色质结构在转录水平上与基因活性有关 活性染色质比非活性染色质对DNAase I更敏感。在……里面 此外，在基因的5‘侧翼区域有一些位置是 当基因活跃时，对脱氧核糖核酸酶I极为敏感。缺席，或 这些位点的碱基变化与缺乏或减少 基因表达。 我们建议研究这种核酸酶的敏感性在玫瑰色的轨迹。 黑腹果蝇。玫瑰色的基因座包含结构基因 黄嘌呤脱氢酶(XDH)及其DNA已被克隆。其表达方式 是发育调节和组织特异性的。有几个 提供包括异染色质位置效应突变体在内的对照突变体 在这个轨迹上。我们已经确定了在控制区的碱基变化 通过DNA测序获得两个低产突变株。 我们希望分析该基因座在野外的DNAase I超敏反应 类型和控制突变体。我们观察到的任何变化都将是相关的 与已知的DNA序列和XDH表达进行比较。这些信息 对该基因座的定向突变工作也很有用。使用 异色位置效应突变体，我们将检查，此外， 活性染色质对DNAase I的一般敏感性。我们假设 异染色质的位置效应是由异染色质凝聚引起的 这样一种方式，使真核染色质中相邻的基因表达减少。 这种浓缩的染色质可能对DNA酶有更强的抗性。 我们与W.Bender‘s和A.Chovnick’s项目的合作努力 实验室已经规划好了。希望我们的共同努力将 有助于理解XdH表达的控制和 监管。

Chromatin structure is related to gene activity in that transcriptionally active chromatin is more susceptible to DNAase I than inactive one. In addition, there are sites at 5' flanking region of a gene which are extremely sensitive to DNAase I when the gene is active. Absence of, or base changes at these sites is correlated with the absence or reduction of gene expression. We propose to study such nuclease sensitivity in the rosy locus of Drosophila melanogaster. The rosy locus contains the structural gene of xanthine dehydrogenase (XDH) and its DNA has been cloned. Its expression is developmentally regulated and tissue specific. There are several control mutants including heterochromatic position effect mutants available in this locus. We have identified base changes in the control region of two underproducer mutants by DNA sequencing. We wish to analyze the DNAase I hypersensitivity of this locus in wild types and control mutants. Any variations we observe will be correlated with the known DNA sequence and the XDH expression. These informations should also be useful for directed mutagenesis work in this locus. With the heterochromatic position effect mutants, we will examine, in addition, a general DNAase I sensitivity of active chromatin. We hypothesize that heterochromatic position effects are due to heterochromatin condensation in such a way that an adjacent gene in eucromatin shows a reduced expression. Such condensed chromatin could be more DNAase resistant. Collaborative efforts of our project with W. Bender's and A. Chovnick's laboratories are planned. It is hoped that our joint efforts will contribute in understanding the control of the XDH expression and regulation.