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Fig. 3 | Rice

Fig. 3

From: The Cornucopia of Small RNAs in Plant Genomes

Fig. 3

The plant miRNA biogenesis pathway and cellular function. The microRNA gene is transcribed by RNA Polymerase (Pol) II. The miRNA precursor, folded into a hairpin structure, is processed by DCL1 and the associated proteins, HYPONASTIC LEAVES1 (HYL1), a double-stranded RNA binding partner, and SERRATE (SER), a zinc-finger containing protein [79, 80]. The miRNA is processed into a miRNA/MiRNA* duplex that is methylated at the 3′ sugars by HUA ENHANCER1 (HEN1) and exported to the cytoplasm by HASTY (HST) [81, 82]. The mature, methylated miRNA is incorporated into the RNA-induced silencing complex (RISC) that includes ARGONAUTE1 (AGO1), which directs cleavage of the target mRNA. The 5′ cleavage product is thought to be degraded by a 3′ to 5′ exosome [83] and the 3′ fragment is degraded by the 5′ to 3′ EXORIBONUCLEASE4 (XRN4) [84]. An alternative decay pathway has also been proposed [84].

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