Homodimerization of HYL1 ensures the correct selection of cleavage sites in primary miRNA.
Bottom Line: Disruption of HYL1 homodimerization causes incorrect cleavage at sites in pri-miRNA without interrupting the interaction of HYL1 with DCL1 and accumulation of pri-miRNAs in HYL1/pri-miRNA complexes, leading to a reduction in the efficiency and accuracy of miRNAs that results in strong mutant phenotypes of the plants.HYL1 homodimers may function as a molecular anchor for DCL1 to cleave at a distance from the ssRNA-dsRNA junction in pri-miRNA.These results suggest that HYL1 ensures the correct selection of pri-miRNA cleavage sites through homodimerization and thus contributes to gene silencing and plant development.
Affiliation: National Key Laboratory of Plant Molecular Genetics, Shanghai Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China.Show MeSH
Mentions: The two dsRBDs, putative protein–protein interaction domain and NLS of HYL1 are indicated in Figure 1A. To determine whether HYL1 forms a homodimer in vitro, we used full-length and truncated HYL1 for a yeast two-hybrid assay. We observed a direct interaction between two HYL1 molecules (Figure 1B). The dsRBD2 fragment interacted with full-length HYL1, whereas the dsRBD1 fragment did not. Moreover, one dsRBD2 fragment interacted with another dsRBD2 but not with dsRBD1. These findings indicate that HYL1 forms a homodimer through the dsRBD2 domains.
Affiliation: National Key Laboratory of Plant Molecular Genetics, Shanghai Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China.