Yijun Qi

 

Email: qiyijun(at)biomed(dot)tsinghua(dot)edu(dot)cn

 

Research Area:
RNA interference is a conserved mechanism of gene regulation in eukaryotes. It plays important roles in diverse biological processes including developmental regulation, antiviral defense and chromatin remodeling. In plants, there are several RNAi pathways. These include post-transcriptional gene silencing (PTGS) mediated by ~21-nt small interfering RNAs (siRNAs), microRNA (miRNA)-mediated mRNA cleavage or translational repression, and transcriptional gene silencing (TGS) that is associated with siRNA-directed chromatin remodeling including DNA and histone methylation. Recently, we discovered a novel class of small RNAs (termed diRNAs) that play important roles in DNA double-strand break (DSB) repair.

We study the mechanisms of plant RNAi using integrated genetic, molecular, biochemical and bioinformatic approaches. Of particular interest are the identification of novel components in RNAi pathways, specialization of RNAi components in different RNAi pathways, the mechanism of diRNA-mediated DSB repair, and the functions of small RNAs in plant physiology and development. In addition to our interest in small RNAs, we are also interested in the biogenesis and function of long non-coding RNAs in plants.

 

Selected Publications:

1. Ye, R., Wang, W., Iki, T., Liu, C., Wu, Y., Ishikawa M., Zhou, X., and Qi, Y. Cytoplasmic assembly and selective nuclear import of Arabidopsis ARGONAUTE4/siRNA complexes. Molecular Cell 46: 859-870，2012.

2. Wei, W., Ba, Z., Gao, M., Wu, Y., Ma, Y., Amiard, S., White, C., Danielsen, J., Yang, Y., and Qi, Y. A role for small RNAs in DNA double-strand break repair. Cell 149:101-112，2012.

3. Wu, L., Mao, L., and Qi, Y. Roles of DICER-LIKE and ARGPNAUTE proteins in TAS-derived small interfering RNA-triggered DNA methylation. Plant Physiology 160: 990-999，2012.

4. Wang, W., Ye, R., Xin, Y., Feng, X., Li, C., Zhou, X., and Qi, Y. (2011). An Importin β protein negatively regulates microRNA activity in Arabidopsis. The Plant Cell, 23: 3565-3576. (Cover story).

5. Wu, L., Zhou, H., Zhang, Q., Ni, F., Liu, C., and Qi, Y. (2010). DNA methylation mediated by a microRNA pathway. Molecular Cell, 38: 465-475 (Cover story). This work was featured in Cell, 141: 556, 2010.

6. Wu, L., Zhang, Q., Zhou, H., Ni, F., Wu, X., and Qi, Y. (2009). Rice microRNA effector complexes and targets. The Plant Cell, 21: 3421-3435.

7. Mi, S., Cai, T., Hu Y., Chen Y., Hodges E., Ni F., Wu L., Li S., Zhou H., Long C., Chen S., Hannon G., and Qi, Y. (2008) Sorting of small RNAs into Arabidopsis Argonaute complexes is directed by the 5’ terminal nucleotide. Cell, 133: 116-127. This work was featured in Cell 133:25-26, 2008.

8. Zhao, T., Li, G., Mi, S., Li, S., Hannon, G., Wang, X.-J., and Qi, Y. (2007). A complex system of small RNAs in the unicellular green alga Chlamydomonas reinhardtii. Genes and Development, 29: 1190-1203. This work was featured in: Cell 129:1029, 2007; Genes and Development 21: 1153-1156, 2007; Nature 447: 5, 2007; Nature 447: 518, 2007; Nature Review Genetics 8: 406, 2007; ACS Chemical Biology 2: 436-437, 2007 .

9. Qi, Y., He, X., Wang X-J., Kohany, O., Jurka, J. and Hannon, G. (2006) Distinct catalytic and non-catalytic roles of ARGONAUTE4 in RNA-directed DNA methylation. Nature, 443: 1008-1012.

10. Qi, Y., Denli, A. and Hannon, G. (2005). Biochemical specialization within Arabidopsis RNA silencing pathways. Molecular Cell , 19: 421-428.