AtFKBP53 is a histone chaperone required for repression of ribosomal RNA gene expression in Arabidopsis  

作　　者：Hong Li Sheng Luan 

机构地区：[1]Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA

出　　处：《Cell Research》2010年第3期357-366,共10页细胞研究（英文版）

基　　金：We thank Veder Garcia （University of California, Berkeley, USA） for critically reading the paper, Zengyong He for providing the AtFKBP53：：GUS transgenic line and Masami Horikoshi （The University of Tokyo, Japan） for the pET-6His-SpFkbp39P plasmid. This work was supported by grants from the National Science Foundation and US Department of Energy （toSL）.

摘　　要：Chromatin structure is important for controlling gene expression, but mechanisms underlying chromatin remodel- ing are not fully understood. Here we report that an FKBP （FK506 binding protein） type immunophilin, AtFKBP53, possesses histone chaperone activity and is required for repressing ribosomal gene expression in Arabidopsis. The At- FKBP53 protein is a multidomain FKBP with a typical peptidylprolyl isomerase （PPIase） domain and several highly charged domains. Using nucleosome assembly assays, we showed that AtFKBP53 has histone chaperone activity and the charged acidic domains are sufficient for the activity. We show that AtFKBP53 interacts with histone H3 through the acidic domains, whereas the PPIase domain is dispensable for histone chaperone activity or histone binding. Ri- bosomal RNA gene （18S rDNA） is overexpressed when AtFKBP53 activity is reduced or eliminated in Arabidopsis plants. Chromatin immunoprecipitation assay showed that AtFKBP53 is associated with the 18S rDNA gene chro- matin, implicating that AtFKBP53 represses rRNA genes at the chromatin level. This study identifies a new histone chaperone in plants that functions in chromatin remodeling and regulation of transcription.

关 键 词：ARABIDOPSIS IMMUNOPHILIN CHROMATIN histone chaperone ribosomal RNA nucleosome assembly 

分 类 号：Q51[生物学—生物化学] S885.212[农业科学—特种经济动物饲养]