Purification of chromatin proteins concerning gene expression in animals and studies on their functions

1.与丝素轻链基因5‘-上游区结合的蛋白质因子：对含有丝素L链基因的粘粒克隆进行序列分析，发现5’-上游区的3个序列，即-415--398，-306--277，-250--226，与丝素H-链基因-275--155区的序列高度同源。结果发现，家蚕后丝腺核0.5M氯化钠抽提物中存在与这三个上游区域结合的蛋白质因子。与-306--277序列的64bp序列结合的蛋白质由后丝腺特异因子(S)和后中丝腺共同因子(S)组成。W-蛋白的纯化和性质：W-蛋白是从鸡肝细胞核的0.35M氯化钠提取液中纯化出来的，在非变性条件下，其单体相对分子质量为72K，但形成约30个分子的多聚体。W蛋白与鸡W染色体特异的弯曲重复DNA(XhoI家族)具有高亲和力。推测XhoI家族序列包裹在W蛋白的多聚体上，通过富含A-T的小凹槽进行多次接触，提示W蛋白参与了染色质高阶结构的形成。

1. Protein factors binding to the 5'-upstream region of the fibroin light(L-) chain gene: Sequence analysis of the cosmid clone containing the fibroin L-chain gene revealed that three sequences in the 5'-upstream region, i.e, -415- -398, -306- -277, -250- -226, were highly homologous to the sequences in the -275- -155 region of the fibroin H-chain gene. It was found that protein factors which bound to the all three upstream regions were present in the 0.5M NaCl extract of the posterior silk gland nuclei of the silkworm, Bombyx mori. Particularly, proteins binding to the 64bp sequence containing the -306- -277 sequence were shown to consist of posterior silk gland-specific factor(s) and posterior and middle silk gland-common factor(s).2. Purification and properties of W-protein: W-protein, purified from the 0.35M NaCl extract of the chicken liver nuclei, has a monomeric molecular weight of 72k but forms a multimeric form consisting of about 30 molecules, under non-denaturing conditions. W-protein binds with high affinity to the chicken W chromosome-specific, bent repetitive DNA(XhoI family). It was suggested that the XhoI family sequence wraps around the multimer of W-protein making multiple contacts through the A-T-rich minor grooves..participation of W-protein in the formation of higher-order structure of chromatin is suggested.