AACR 2014 --Ryuji Hamamoto

Abstract Number: 5156
Presentation Title: The oncogenic polycomb histone methyltransferase EZH2 methylates lysine 120 on histone H2B and competes ubiquitination in human cancer
Presentation Time: Wednesday, Apr 09, 2014, 8:00 AM -12:00 PM
Location: Hall A-E, Poster Section 17
Poster Board Number: 23
Author Block: , Yusuke Nakamura. The University of Chicago, Chicago, IL
Abstract Body: The histone methyltransferase EZH2 is known to be a polycomb protein homologus to Drosophila enhancer of zeste and catalyzes the addition of methyl groups to histone H3 at lysine 27 (H3K27). We previously reported that EZH2 was overexpressed in various types of cancer and plays a crucial role in the cell cycle regulation of cancer cells. In this study, we demonstrated that EZH2 has the function to mono-methylated lysine 120 on histone H2B (H2BK120). EZH2-dependent H2BK120 methylation in cancer cells was confirmed with an H2BK120 methylation-specific antibody. Overexpression of EZH2 significantly attenuated the ubiquitination of H2BK120, a key post-translational modification of histones for transcriptional regulation. Concordantly, knockdown of EZH2 increased the ubiquitination level of H2BK120, suggesting that the methylation of H2BK120 by EZH2 may competitively inhibit the ubiquitination of H2BK120. Subsequent ChIP-Seq and microarray analyses identified downstream candidate genes regulated by EZH2 through the methylation of H2BK120. This is the first report to describe a novel substrate of EZH2, H2BK120, unveiling a new aspect of EZH2 functions in human carcinogenesis.
[[unable to display character:  ]]