A Role for the F-Box Protein HAWAIIAN SKIRT in Plant microRNA Function.

As regulators of gene expression in multicellular organisms, microRNAs (miRNAs) are crucial for growth and development. Although a plethora of factors involved in their biogenesis and action in Arabidopsis () has been described, these processes and their fine-tuning are not fully understood. Here, we used plants expressing an artificial miRNA target mimic (MIM) to screen for negative regulators of miR156.

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

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.