Identification of a Ubiquitin-Binding Structure in the S-Locus F-Box Protein Controlling S-RNase-Based Self-Incompatibility  

作　　者：Guang Chen BinZhang Lijing Liu Qun Li Yu'e Zhang Qi Xie Yongbiao Xue 

机构地区：[1]State Key Laboratory of Molecular Developmental Biology,Institute of Genetics and Developmental Biology,Chinese Academy of Sciences and National Center for Plant Gene Research,Beijing 100101,China [2]State Key Laboratory of Plant Genomics,Institute of Genetics and Developmental Biology,Chinese Academy of Sciences and National Center for Plant Gene Research,Beijing 100101,China [3]Graduate University of Chinese Academy of Sciences,Beijing 100190,China

出　　处：《Journal of Genetics and Genomics》2012年第2期93-102,共10页遗传学报（英文版）

基　　金：supported by the National Basic Research Program of China(973 Program)(Nos.2007CB108703 and 2011CB915404);the National Natural Science Foundation of China(No.30921003)

摘　　要：In flowering plants, self-incompatibility （SI） serves as an important intraspecific reproductive barrier to promote outbreeding. In species from the Solanaceae, Plantaginaceae and Rosaceae, S-RNase and SLF （S-locus F-box） proteins have been shown to control the female and male specificity of SI, respectively. However, little is known about structure features of the SLF protein apart from its conserved F-box domain. Here we show that the SLF C-terminal region possesses a novel ubiquitin-binding domain （UBD） structure conserved among the SLF protein family. By using an ex vivo system of Nicotiana benthamiana, we found that the UBD mediates the SLF protein turnover by the ubiquitin-proteasome pathway. Furthermore, we detected that the SLF protein was directly involved in S-RNase degradation. Taken together, our results provide a novel insight into the SLF structure and highlight a potential role of SLF protein stability and degradation in S-RNase-based self-incompatibility.In flowering plants, self-incompatibility （SI） serves as an important intraspecific reproductive barrier to promote outbreeding. In species from the Solanaceae, Plantaginaceae and Rosaceae, S-RNase and SLF （S-locus F-box） proteins have been shown to control the female and male specificity of SI, respectively. However, little is known about structure features of the SLF protein apart from its conserved F-box domain. Here we show that the SLF C-terminal region possesses a novel ubiquitin-binding domain （UBD） structure conserved among the SLF protein family. By using an ex vivo system of Nicotiana benthamiana, we found that the UBD mediates the SLF protein turnover by the ubiquitin-proteasome pathway. Furthermore, we detected that the SLF protein was directly involved in S-RNase degradation. Taken together, our results provide a novel insight into the SLF structure and highlight a potential role of SLF protein stability and degradation in S-RNase-based self-incompatibility.

关 键 词：Protein degradation SLF UBIQUITIN SELF-INCOMPATIBILITY Ubiquitin-binding structure S-RNASE 

分 类 号：S661.203.6[农业科学—果树学] S635[农业科学—园艺学]