In PNAS: Role of RCF as a HYL1 cofactor in miRNA biogenesis

The KH domain protein RCF3 is a tissue-biased regulator of the plant miRNA biogenesis cofactor HYL1

Karlsson, P., Christie, M.D., Seymour, D., Wang, H., Wang, X., Hagmann, J., Kulcheski, F.R. and Manavella, P.A.

The biogenesis of microRNAs (miRNAs), which regulate mRNA abundance through posttranscriptional silencing, comprises multiple well-orchestrated processing steps. We have identified the Arabidopsis thaliana K homology (KH) domain protein REGULATOR OF CBF GENE EXPRESSION 3 (RCF3) as a cofactor affecting miRNA biogenesis in specific plant tissues. MiRNA and miRNA-target levels were reduced in apex-enriched samples of rcf3 mutants, but not in other tissues. Mechanistically, RCF3 affects miRNA biogenesis through nuclear interactions with the phosphatases C-TERMINAL DOMAIN PHOSPHATASE-LIKE1 and 2 (CPL1 and CPL2). These interactions are essential to regulate the phosphorylation status, and thus the activity, of the double-stranded RNA binding protein and DICER-LIKE1 (DCL1) cofactor HYPONASTIC LEAVES1 (HYL1)