尖尾藻的染色质碱性蛋白研究  

STUDIES ON BASIC CHROMATIN PROTEINS OF DINOFLAGELLATE OXYRRHIS MARINA

作　　者：文建凡[1] 李靖炎[1] 

机构地区：[1]中国科学院昆明动物研究所细胞与分子进化开放实验室

出　　处：《动物学报》1998年第3期347-352,共6页ACTA ZOOLOGICA SINICA

摘　　要：利用“先固定后抽提”的方法，从尖尾藻细胞中提取出染色质碱性蛋白。经ＳＤＳＰＡＧＥ分析，结果显示此染色质碱性蛋白含有八个组分（记为１′、１″、２ａ、２ｂ、３′、３″、４′、４″），它们像小牛胸腺组蛋白一样形成两个分子量区域，即一为对应组蛋白Ｈ１的分子量区域，另一为对应于核心组蛋白（即Ｈ２Ａ，Ｈ２Ｂ，Ｈ３，Ｈ４）的分子量区域；其与组蛋白各组分的具体对应关系大致为：对应于小牛胸腺组蛋白Ｈ１两亚带区域有两条带１′、１″，对应于Ｈ３附近有两条带３′、３″，对应于Ｈ２Ａ、Ｈ２Ｂ分别有２ａ、２ｂ两带，对应于Ｈ４也有两条带４′、４″。激光密度扫描结果也清楚地显示出上述这些电泳带所对应的扫描峰。文中讨论了涡鞭毛虫类的进化地位。In most of the previous work, basic chromatin proteins (BCP) were isolated from dinoflagellates by the method which was invented for isolating histones from higher eukaryotes. But we have recently proved that this conventional method is not so suitable for the lower eukaryotes. In fact, the previous contradictory reports of BCP in dinoflagellates have reflected such a problem to a certain extent. For example, two reports showed that dinoflagellate Oxyrrhis marina had 1 and 2 BCP(s), respectively. We have established a procedure called “prefixation and acid extraction' which avoids the above problem completely due to the methanol prefixation step before extraction of BCPs. By this procedure, BCPs were isolated from O. marina. SDS PAGE analysis showed they contained 8 fractions, which had similar electrophoretic patterns with the five histone fractions of calf thymus. Considering the advantage of our procedure over the conventional method, this result should be more reliable than the previous one. Most of the previous work had reported that dinoflagellates did not possess histone but contained 1～2 basic chromatin proteins, and some researchers thought the latter might be the ancestor of histones. According to the present work, in addition to our other work, we argue that BCPs of dinoflagellates are of diversity, and some dinoflagellates have much more than 1～2 BCPs which are similar to histones or are histones. The result support the opinion that “ the histones were secondarily lost in dinoflagellate' and were replaced gradually by other basic proteins. So dinoflagellates are not as primitive as what they were thought before, and the similarity of their chromosomes to nucleoid of bacteria might be a secondary revolutionary event after the loss of histones.

关 键 词：涡鞭毛虫 尖尾藻 染色质碱性蛋白 进化 

分 类 号：Q51[生物学—生物化学]