RISC-interacting clearing 3’- 5’ exoribonucleases (RICEs) degrade uridylated cleavage fragments to maintain functional RISC in Arabidopsis thaliana

eLife

Fuqu Hu¹  Chang Shu¹  Martin Dickman¹  Min Woo Sung²  Claudia Castillo-González²  Guiliang Tang²  Zhonghui Zhang²  Hisashi Koiwa²  Xiuren Zhang³  Pingwei Li⁴ 

[1] Institute for Plant Genomics and Biotechnology, Texas A&M University, College Station, United States;Department of Biochemistry and Biophysics, Texas A&M University, College Station, United States;Department of Biological Sciences, Michigan Technological University, Houghton, United States;Department of Horticulture, Texas A&M University, College Station, United States;

关键词: argonaute;    RICE;    exoribonuclease;    miRNAs;    RISC;    uridylation;   

DOI  :  10.7554/eLife.24466

来源: DOAJ

【 摘 要 】

RNA-induced silencing complex (RISC) is composed of miRNAs and AGO proteins. AGOs use miRNAs as guides to slice target mRNAs to produce truncated 5' and 3' RNA fragments. The 5' cleaved RNA fragments are marked with uridylation for degradation. Here, we identified novel cofactors of Arabidopsis AGOs, named RICE1 and RICE2. RICE proteins specifically degraded single-strand (ss) RNAs in vitro; but neither miRNAs nor miRNA*s in vivo. RICE1 exhibited a DnaQ-like exonuclease fold and formed a homohexamer with the active sites located at the interfaces between RICE1 subunits. Notably, ectopic expression of catalytically-inactive RICE1 not only significantly reduced miRNA levels; but also increased 5' cleavage RISC fragments with extended uridine tails. We conclude that RICEs act to degrade uridylated 5’ products of AGO cleavage to maintain functional RISC. Our study also suggests a possible link between decay of cleaved target mRNAs and miRNA stability in RISC.

【 授权许可】

Unknown