新发现的着丝粒蛋白CENP-G的基因克隆和功能研究

CenpG is a centromere protein discovered by He Dacheng, a member of our group. The current research project has studied the role of CenpG in centromere structure and its functions in cell proliferation, canceration, apoptosis and so on, explored the functions of several known or newly discovered centromere proteins and their relationships, and screened cDNA library with anti-CenpG serum and done relevant gene clonings. The major results are as follows: (1) CenpB and CenpG were both testified as centromeric structural proteins. They are both related to the states of cell proliferation. The differential expressing of CenpG (together with it, there may be other relative genes) probably relates to malignant cell proliferation, and moreover, a kind of protein component whose molecular weight is 43kd , and which can be recognized by anti-CenpG serum was found in 2 of breast cancer samples. （2）The inhibition of the expressions of CenpB and CenpG affect the assembly of centromere, but their expressing levels are both regulated cell cycle relevantly, so as not to change their proportions among all mitotic phases distinctly. （3）CenpB and CenpG relate to each other closely in centromere structure and function. The complexes they form with α-DNA are important basis for the centromere structure formation. （4）Among the 5 positive clones screened from cDNA library by using anti-CenpG serum, both the cDNA fragments of 2 clones are the same of the 3'-end of centromere gene CenpC. Another one is dual specifically phosphataseⅢ total cDNA. The other 2 are both new genes, one of which (13-12gene）encodes dual specifically phosphatase Ⅲ which is located in centrosome. Centromere and centrosome are both important mitotic apparatuses. They play important roles in cell cycle checkpoint control. In addition, over 100 sera of auto-immune diseases were screened were special antibodies. A new centromere protein of 66kd (66kdCenp) was discovered in mammals. （5）It was revealed that many other ACA sera (anti-centromere protein anti-sera) cannot recognize any antigen in Urechis unicinctus （Echiuroidea），and that CenpG and 66kdCenp antigens, however, exist in it, which shows evoutionary conservatism. The cell-killing and apoptosis-inducing effects of anti-leukemia Drug Harringtonine (HT) may be mediated by the inhibition of the expressions of CenpB, CenpG and other centromere protein genes. But we discovered a centromere protein with a molecular weight of 66kd（66kdCenp），and its expressing level increases with the increases of HT treatment dose and the prolongation of its duration. (6）The results of the current project lay a new foundation for the exploration on the molecular basis of cell proliferation regulation.

着丝粒蛋白（CENP－G）对着丝粒处染色质的正确组装、纺锤体组装检验点的调控、动粒功艿恼肥迪帧⑷旧宓淖既贩掷爰跋赴芷谡Ｔ诵械确矫婢兄匾饔谩Ｗ罱⑾郑恢治格疾垦芾┱胖⒉∪说难蹇固宄煞帜苁侗餒eLa细胞核蛋白提取物中的95kD CENP抗原（我们定名为CENP－G）。本研究旨在获得CENP－G的单抗和基因序列，并研究其性质和功能，对探讨着丝粒的结构和功能、细胞增殖和癌化的机理有重要意