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

The biogenesis of microRNAs (miRNAs), which regulate mRNA abundance through post-transcriptional silencing, comprises multiple well-orchestrated processing steps. We have identified Arabidopsis thaliana RCF3 as a tissue-specific miRNA biogenesis cofactor. MiRNA and miRNA-target levels were reduced in apices and apex-enriched samples of rcf3 mutants, but not in other tissues. Mechanistically, RCF3 affects miRNA biogenesis through nuclear interactions with the phosphatases CPL1 and CPL2. These interactions are essential to regulate the phosphorylation status, and thus the activity, of the double-stranded RNA binding protein and DCL1 cofactor HYL1