The long-term goal of my research is to study functions and biochemical mechanisms of RNA silencing in plants. RNA silencing is a key regulatory process that controls various aspects of biology in eukaryotes including growth and development, stress responses, and antiviral defense. RNA silencing is guided by tiny regulatory RNA molecules called miRNAs or siRNAs that are widely present in multicellular organisms. In humans, miRNAs inhibit more than 60 percent of human genes and are actively exploited as potent drugs to cure human diseases. In plants, the molecules are also widely engineered in agricultural crops and animals for better yield and quality.
The common biochemical themes of RNA silencing include the biogenesis of small RNAs by DICERs, and the incorporation of small RNAs into Argonaute (AGO)-centered RNA-induced silencing complexes (RISCs). The RISCs execute the repressive or regulatory functions on target genes at the transcriptional or post-transcriptional levels. Our research has now extended from RNA silencing to RNA-centered biology in plants and also beyond plants. Our search include five major aspects: 1) RISC functions and mechanism using Arabidopsis AGO10 as an example; 2) how is miRNA produced in plants; 3) how RNA secondary structures are remodeled and how the process interplays with epi-transcript modifications; 4) crosstalk between transcriptional gene silencing (TGS) and posttranscriptional gene silencing (PTGS); and 5) Epigenetic silencing and viral suppressors. Accordingly, we have made significant accomplishments in all of these five directions.