最新一期Molecular Cell杂志上,美国密歇根大学副教授窦雅丽小组发表了有关MOF的研究成果,提出了一种新型的调控机制。
MYST组蛋白乙酰转移酶(histone acetyltransferase, HAT)广泛存在于从酵母到人的真核生物中,在真核生物的转录调控中起着重要的作用,这一家族中MOF蛋白在转录活性中扮演着重要的角色——组蛋白H4乙酰转移至K16。MOF基因长1575bp(GenBank登录号为DQ442997),开放阅读框(ORF)长1326bp,无内含子,基因编码442个氨基酸,预测蛋白质的分子量为51.4kD,序列中有HAT核心结构域、锌指结构域和染色质域3个保守的结构域,与其他物种同源基因具有较高的序列相似性。
到目前为止,虽然已经获得了一些MOF调控方面的研究成果,但是在高等真核生物中,科学家们还不是很清楚MOF的调控机制和模式。在这篇文章中,研究人员在两组进化上保守的不同复合物:MSL和MOF-MSL1v1中分析MOF的乙酰转移酶活性。
他们发现虽然这两种MOF复合物在组蛋白H4K16的活性方面存在较小差异,但是在对底物p53这种非组蛋白的作用活性方面却存在极大差异。进一步研究证明MOF-MSF 1v1是一种无论体内,还是体外实验中,p53靶基因获得最佳转录活性的必需因子,这些研究结果提出了一种新型的作用模型:两个MOF复合物能与其它组蛋白修饰活性因子一起调控转录活性的不同阶段。(生物谷Bioon.com)
生物谷推荐原始出处:
Molecular Cell,23 October 2009 doi:10.1016/j.molcel.2009.07.031
Two Mammalian MOF Complexes Regulate Transcription Activation by Distinct Mechanisms
Xiangzhi Li1, Lipeng Wu1, Callie Ann Sprunger Corsa1, Steve Kunkel1 and Yali Dou1, 2, ,
1 Department of Pathology, University of Michigan, Ann Arbor, MI 48109, USA
2 Department of Biological Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
In mammals, MYST family histone acetyltransferase MOF plays important roles in transcription activation by acetylating histone H4 on K16, a prevalent mark associated with chromatin decondensation, and transcription factor p53 on K120, which is important for activation of proapoptotic genes. However, little is known about MOF regulation in higher eukaryotes. Here, we report that the acetyltransferase activity of MOF is tightly regulated in two different but evolutionarily conserved complexes, MSL and MOF-MSL1v1. Importantly, we demonstrate that while the two MOF complexes have indistinguishable activity on histone H4 K16, they differ dramatically in acetylating nonhistone substrate p53. We further demonstrate that MOF-MSL1v1 is specifically required for optimal transcription activation of p53 target genes both in vitro and in vivo. Our results support a model that these two MOF complexes regulate distinct stages of transcription activation in cooperation with other histone modifying activities.