アクティブボード・２０１５年　１月
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研究発表を行った学会；
・第３７回日本分子生物学会年会
　２０１４年１１月２５日〜２７日（横浜）
タイトル；Novel roles of centromeric non-coding RNP in regulation of sister chromatid cohesion.
発表者；長　裕紀子　氏
　　　（熊本大学　大学院自然科学研究科　谷研究室）
Abstract；
Human centromere consists of repetitive sequences that generate non-coding RNAs. Satellite I RNA is one of ncRNAs transcribed from centromere. To investigate functions of Sat I RNA, we carried out knockdown of Sat I RNA using anti-sense oligo. Sat I RNA depleted HeLa cells showed the Grape shape phenotype, the abnormal nuclear morphology caused by defects of chromosome segregation. We found that Aurora B, a key factor of chromosome segregation, associates with Sat I RNA. Interestingly, in Sat I RNA depleted cells, Aurora B showed elevated kinase activity and its mis-localization from centromeres. It is suggesting that Sat I RNA regulate chromosome segregation through the control of Aurora B function. Chromosome spread revealed that depletion of Sat I RNA causes defective centromeric cohesion of sister chromatids. To investigate roles of Sat I RNA in this process, we examined proteins associated with Sat I RNA by purification of Sat I RNP and identified RBMX as one of components of Sat I RNP. RBMX is known to associate with protein interact with cohesin. Knockdown of RBMX caused defects in chromosome segregation and chromatid cohesion. Furthermore, RBMX dissociated from chromatin fraction in Sat I RNA depleted cells. Sororin is one of regulators for cohesion. Knockdown of Sororin resulted in abnormal cohesion and defective chromosome segregation. Phosphorylation of Sororin by Aurora B causes dissociation of Sororin from cohesin. We speculated that, in Sat I RNA depleted cells, elevated activity of Aurora B affects function of Sororin to regulate the cohesion. These results suggest that Sat I RNP regulates chromosome segregation through the control of chromatid cohesion.