McBurney Kristina L, Leung Andrew, Choi Jennifer K, Martin Benjamin J E, Irwin Nicholas A T, Bartke Till, Nelson Christopher J, Howe LeAnn J
Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z3.
Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, Canada V8P 5C2.
Genetics. 2016 Jan;202(1):341-9. doi: 10.1534/genetics.115.180810. Epub 2015 Nov 3.
Histones are among the most conserved proteins known, but organismal differences do exist. In this study, we examined the contribution that divergent amino acids within histone H3 make to cell growth and chromatin structure in Saccharomyces cerevisiae. We show that, while amino acids that define histone H3.3 are dispensable for yeast growth, substitution of residues within the histone H3 α3 helix with human counterparts results in a severe growth defect. Mutations within this domain also result in altered nucleosome positioning, both in vivo and in vitro, which is accompanied by increased preference for nucleosome-favoring sequences. These results suggest that divergent amino acids within the histone H3 α3 helix play organismal roles in defining chromatin structure.
组蛋白是已知最保守的蛋白质之一，但生物体之间的差异确实存在。在本研究中，我们研究了组蛋白H3中不同氨基酸对酿酒酵母细胞生长和染色质结构的影响。我们发现，虽然定义组蛋白H3.3的氨基酸对酵母生长并非必需，但将组蛋白H3 α3螺旋内的残基替换为人源对应残基会导致严重的生长缺陷。该结构域内的突变还会导致体内和体外核小体定位改变，同时对核小体偏好序列的偏好增加。这些结果表明，组蛋白H3 α3螺旋内的不同氨基酸在定义染色质结构中发挥着生物体特异性作用。
