DEVELOPMENT OF SALIVARY GLAND PROTEINS

黑腹果蝇的Sgs-4基因座编码一个发育上的 在幼虫唾液腺中大量产生的调节蛋白质， 作为蛹胶的一部分 该提案提出了几种方法来检查 Sgs-4表达。 将使用Sgs-4突变体之间的遗传重组 以在Sgs-4的5'侧定位调节区。 遗传 交叉点将通过DNA印迹分析来定义。 重组染色体 以这种方式定义的区域将在 通过SGS-4突变体的DNA序列分析更详细地描述。 有一张纸巾 Sgs-4的5'侧染色质结构的特异性变化， 基因活跃。 这一结构变化被检测为一个网站在 对DNA酶I消化高度敏感的染色质。 的参与 Sgs-4表达中的这个位点将通过在 Sgs-4突变体的染色质，并通过确定在发育过程中， 出现. 超敏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 核酸酶消化以定位核小体5'到Sgs-4，当基因被 活跃或不活跃。 最后，蛋白质和DNA序列的要求 将研究DNA酶超敏感位点体外形成。

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.