DEVELOPMENT OF SALIVARY GLAND PROTEINS

果蝇SGS-4基因座编码发育中的 在幼虫唾液腺中大量制造和使用的调节蛋白 作为蛹胶水的一部分。这项建议提出了几种检查方法 SGS-4的表达。将使用SGS-4突变体之间的遗传重组 定位SGS-4基因5‘端的调控区域。基因 交叉点将通过Southern杂交分析确定 重组染色体。将在中检查以这种方式定义的区域 通过对SGS-4突变体的DNA序列分析，获得了更详细的信息。有一张纸巾 SGS-4基因5‘端染色质结构的特异性变化 吉恩很活跃。此结构更改被检测为 对DNase I消化高度敏感的染色质。参与其中的 在SGS-4表达中的这个站点将通过在 SGS-4突变体的染色质及其在发育过程中的确定 出现了。过敏性位点的形成可能影响SGS-4 通过改变核小体5‘端附近的组织来表达 基因。这种可能性将使用部分微球菌进行检查。 核酸酶消化以定位5‘至SGS-4的核小体 活动或非活动。最后，对蛋白质和DNA序列的要求 在体外，将研究DNA酶敏感部位的形成。

The Sgs-4 locus in Drosophila melanogaster codes for a developmentally regulated protein made in large amounts in larval salivary glands and used as part of the pupal glue. This proposal suggests several ways to examine Sgs-4 expression. Genetic recombination between Sgs-4 mutants will be used to locate a regulatory region on the 5' side of Sgs-4. The genetic crossover points will be defined by Southern blot analysis of the recombinant chromosomes. The region defined this way will be examined in more detail by DNA sequence analysis of SGS-4 mutants. There is a tissue specific change in chromatin structure on the 5' side of Sgs-4 when the gene is active. This structural change is detected as a site in the chromatin which is hypersensitive to DNase I digestion. The involvement of this site in Sgs-4 expression will be examined by looking for it in the chromatin of Sgs-4 mutants and by determining when during development it appears. Formation of the hypersensitive site might affect Sgs-4 expression by altering the organization of nucleosomes near the 5' end of the gene. This possibility will be examined using partial micrococcal nuclease digestion to locate the nucleosomes 5' to Sgs-4 when the gene is active or inactive. Finally the protein and DNA sequence requirements for in vitro formation of a DNase hypersensitive site will be investigated.