2013 Fiscal Year Final Research Report

The nucleolus regulates hematopoietic cell differentiation

Research Project

Project/Area Number	24770178
Research Category	Grant-in-Aid for Young Scientists (B)
Allocation Type	Multi-year Fund
Research Field	Cell biology
Research Institution	Doshisha University
Principal Investigator	KURODA Takao 同志社大学, 高等研究教育機構, 助教 (30620637)
Project Period (FY)	2012 – 2013
Keywords	核小体 / リボソームRNA / 血球系細胞分化
Research Abstract	In this study, I have tried to address the role of the nucleolus in cellular differentiation. I found that rRNA transcription was downregulated during hematopoietic differentiation in both human leukemia cell line and mouse hematopoietic stem cells. In response to the inhibition of rRNA transcription, nucleolar protein MYBBP1A was translocated from the nucleolus to the nucleoplasm and interacted with c-Myc, which is one of the master regulator of hematopoietic differentiation. MYBBP1A attenuated transcriptional activity of c-Myc and promoted megakaryocytic differentiation. I also found that hematopoietic differentiation was sufficiently induced by specific suppression of rRNA transcription using actinomycin D or siRNA for TIF-IA. These results suggest that the downregulation of rRNA transcription accelerates cellular differentiation at least in hematopoietic cells.