- Graduate Education
- M.S. Auburn University (1999)
- Ph.D Cornell University (2003)
- Postdoc: Rockefeller University (2003-2008)
- Joined Texas A&M in 2008
- NSF CAREER Award 2013
AGOs-mics / RNA silencing and viral suppression
RNA silencing has emerged as a key regulatory process that controls various aspects of biology in eukaryotes including growth and development, antiviral defense and chromosome gardening. The common themes under RNA silencing include the biogenesis of small RNAs by DICERs and the incorporation of the 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 laboratory focuses on systemic analysis of biochemical, molecular and biological functions of AGO family proteins (AGOs-mics) in genetically tractable Arabidopsis and economically important crops (i.e. rice). We’d like to identify the small RNAs, mRNA targets and protein components which associate with these AGOs. We will study protein/RNA and protein/protein interactions in these RISC assembly events. Our goal is to understand how these AGOs are functionally specialized or redundant corresponding to endogenous development cues and external environmental stimuli. Particularly, we’d like to learn how plants reprogram their gene expression through the small RNAs and AGOs to construct a new cellular niche in responses to environmental challenges and biotic stresses.
Another aspect of our research involves host/virus interaction. Plants take advantage of RNA silencing pathways to defend themselves from exogenous nucleic acid invaders (i.e. viruses). As an anti-host defense mechanism, viruses encode suppressors that can block RNA silencing responses. We have recently demonstrated that CMV 2b disables AGO1 cleavage activity to inhibit RNA silencing and to counter host defense. We are now extending our study to suppressors of several other viruses and the molecular mechanisms of their suppression.
Ma, Z, Zhang, X. Actions of plant Argonautes: predictable or unpredictable? Curr. Opin. Plant Biol. 2018;45 (Pt A):59-67.
Wang, Z, Ma, Z, Castillo-González, C, Sun, D, Li, Y, Yu, B et al.. SWI2/SNF2 ATPase CHR2 remodels pri-miRNAs via Serrate to impede miRNA production. Nature. 2018;557 (7706):516-521.
Castillo-González, C, Zhang, X. Transactivator: A New Face of Arabidopsis AGO1. Dev. Cell. 2018;44 (3):277-279.
Mei, Y, Yang, X, Huang, C, Zhang, X, Zhou, X. Tomato leaf curl Yunnan virus-encoded C4 induces cell division through enhancing stability of Cyclin D 1.1 via impairing NbSKη -mediated phosphorylation in Nicotiana benthamiana. PLoS Pathog. 2018;14 (1):e1006789.
Fukudome, A, Sun, D, Zhang, X, Koiwa, H. Salt Stress and CTD PHOSPHATASE-LIKE4 Mediate the Switch between Production of Small Nuclear RNAs and mRNAs. Plant Cell. 2017;29 (12):3214-3233.
Zhang, X. Tough GC beats transgene silencing. Nat Plants. 2017;3 (11):850-851.
Zhang, Z, Hu, F, Sung, MW, Shu, C, Castillo-González, C, Koiwa, H et al.. RISC-interacting clearing 3'- 5' exoribonucleases (RICEs) degrade uridylated cleavage fragments to maintain functional RISC in Arabidopsis thaliana. Elife. 2017;6 :.
Zhang, Z, Guo, X, Ge, C, Ma, Z, Jiang, M, Li, T et al.. KETCH1 imports HYL1 to nucleus for miRNA biogenesis in Arabidopsis. Proc. Natl. Acad. Sci. U.S.A. 2017;114 (15):4011-4016.
Li, S, Castillo-González, C, Yu, B, Zhang, X. The functions of plant small RNAs in development and in stress responses. Plant J. 2017;90 (4):654-670.
Zhang, Z, Liu, X, Guo, X, Wang, XJ, Zhang, X. Arabidopsis AGO3 predominantly recruits 24-nt small RNAs to regulate epigenetic silencing. Nat Plants. 2016;2 (5):16049.