Rice Papers

Plant Cell Advance November 10, 2009

Rice MicroRNA Effector Complexes and Targets

NIBS鎴氱泭鍐涚殑鏂囩珷锛屽崡鍐滅殑鏉板嚭鏍″弸锛宮iRNA澶у閮戒笉闄岀敓锛屽拰AGO铔嬬櫧缁撳悎鎶戝埗杞綍鏉ヤ笅璋冨熀鍥犺〃杈撅紝姘寸ɑ涓湁4涓狝GO1锛屽垎鍒懡鍚嶄负a,b,c,d锛屽埄鐢≧NAi鐨勬柟娉曟潵涓嬭皟杩�4涓狝GO鐨勮〃杈句骇鐢熶簡寰堝鍙戣偛涓婄殑琛ㄥ瀷骞朵笖瀵艰嚧鍏秚argets鐨勭Н绱�侫GO1a,AGO1b, and AGO1c鐨勫鍚堢墿琚函鍖栧嚭鏉ュ仛杩涗竴姝ョ殑鍒嗘瀽锛岃繖涓変釜AGO1鍊惧悜浜庣粨鍚�5′ U鐨勫皬RNA锛岃�屼笖鍏锋湁Slicer activity銆傞�氳繃娣卞害娴嬪簭鍙戠幇杩欎笁涓狝GO1閮界粨鍚堜竴浜涘凡鐭ョ殑miRNAs锛屽ぇ閮ㄥ垎鐨刴iRNAs閮藉潎鍖�鐨勫垎甯冭繖涓変釜AGO1閲岋紝璇存槑鍏锋湁鍐椾綑鎬э紝鍚屾椂鏈変竴浜沵iRNAs鍦ㄤ笉鍚岀殑AGO1閲岄潰璇存槑鍙堝叿鏈夌壒寮傛�с�傝繘涓�姝ワ紝鎴戜滑鏈夊ぇ瑙勬ā鐨勯壌鍒嚭姘寸ɑ鐨刴iRNA鐨則argets锛岃繖浜涘凡鐭ョ殑targets渚嬪杞綍鍥犲瓙涓湁鐨勬槸鎺у埗鍙戣偛涓婄殑琛ㄥ瀷锛屾湁鐨勬帶鍒跺绉嶇敓鐞嗚繃绋嬶紝璇存槑miRNA鍦ㄦ按绋讳腑鍏锋湁骞挎硾鐨勮皟鎺т綔鐢ㄣ��

MicroRNAs (miRNAs) are small silencing RNAs with regulatory roles in gene expression. miRNAs interact with Argonaute (AGO) proteins to form effector complexes that cleave target mRNAs or repress translation. Rice (Oryza sativa) encodes four AGO1 homologs (AGO1a, AGO1b, AGO1c, and AGO1d). We used RNA interference (RNAi) to knock down the four AGO1s. The RNAi lines displayed pleiotropic developmental phenotypes and had increased accumulation of miRNA targets. AGO1a, AGO1b, and AGO1c complexes were purified and further characterized. The three AGO1s all have a strong preference for binding small RNAs (sRNAs) with 5′ U and have Slicer activity. We cataloged the sRNAs in each AGO1 complex by deep sequencing and found that all three AGO1s predominantly bound known miRNAs. Most of the miRNAs were evenly distributed in the three AGO1 complexes, suggesting a redundant role for the AGO1s. Intriguingly, a subset of miRNAs were specifically incorporated into or excluded from one of the AGO1s, suggesting functional specialization among the AGO1s. Furthermore, we identified rice miRNA targets at a global level. The validated targets include transcription factors that control major stages of development and also genes involved in a variety of physiological processes, indicating a broad regulatory role for miRNAs in rice.