Identification of DCL1-mediated microRNA biogenesis in green alga .

In eukaryotes, microRNAs (miRNAs) are generated by Dicer/Dicer-Like (DCL)-mediated cleavage. Previous studies identified three DCL genes (DCL1-3) in and indicated that DCL3 mediated the production of most miRNAs, while DCL1 protein was mainly involved in siRNA biogenesis. The role of DCL1 in miRNA biogenesis remains unclear. This study constructed a phylogenetic tree, performed structural analyses of Dicer/DCL proteins from multiple species and screened and verified and mutant strains. Using CC-5325 and mutant as control groups, we performed sRNA-sequencing, RT-qPCR, and Northern blot verification experiments on mutant to explore the involvement of DCL1 in miRNA biogenesis in . The results demonstrated that DCL1 was involved in the production of 22 miRNAs, including cre-miR910, novel-miR01, novel-miR03, novel-miR04, novel-miR05, and novel-miR06, whose production was depended not only on DCL1 but also on DCL3. The present findings highlight the production of some miRNAs that may be involved in multiple DCL proteins, which is different from animals and plants. The results of this study will enrich the knowledge of miRNA biogenesis in eukaryotes.