Search for chromation proteins responsible for regulation of gene expression in animal cells

1)分析了丝素蛋白h链基因的染色质结构及其在蜕皮周期中组织特异性和阶段特异性表达的关系。从家蚕4龄和5龄幼虫的后丝腺中分离的核中，h链基因对dna酶I、微球菌核酸酶和一些限制性内切酶（PstI、HhaI、AluI等）的消化极为敏感，h链基因在这些核中表达活跃。另一方面，在第4蜕皮期后丝腺的细胞核或不表达h链基因的中丝腺的细胞核对这些核酸酶的作用变得极具抗性。2)丝素蛋白H链和l链基因位于不同的染色体上，但其表达受到协调控制。测定了完整的cDNA序列和部分l链基因组序列。l链基因-415 ~ -226的上游序列元件与h链基因-273 ~ -193的上游序列元件相同。3)从雌鸡肝细胞核中分离到约72kDa的染色质蛋白（“W蛋白”）。W蛋白与家鸡（Gallus Gallus domesticus）的W染色体特异性重复DNA单元具有高亲和力。

1) Chromatin structure of the fibroin H-chain gene was analyzed in relation to its tissue-specific and stage-specific expression during the molting cycle. The H-chain gene is extremely sensitive to the digestion with DNase I, micrococcal nuclease, and some restriction enzymes(PstI, HhaI, AluI, etc.) in the nuclei isolated from the posterior silk glands of the 4th and 5th instar larvae of Bombyx mori, where expression of the H-chain gene is active. On the other hand, it becomes extremely resistant to the action of these nucleases in the nuclei from the posterior silk glands at the 4th molting stage or in the nuclei from the middle silk glands, where the H-chain gene is not expressed.2) Fibroin H- and L-chain genes are located on different chromosomes, but their expression is controlled coordinately. The complete cDNA sequence and part of the genomic sequence of the L-chain were determined. Three upstream sequence elements within the -415 to -226 of the L-chain gene were found to be identical with those present in the -273 to -193 region of the H-chain gene.3) A chromatin protein of about 72kDa("W protein") was isolated from the nuclei of the female chicken liver. The W protein binds with high affinity to the W chromosome-specific repetitive DNA unit of the domestic fowl, Gallus gallus domesticus.