Recently, a new progress in mRNA surveillance mechanism in plants was done by research group of Department of Plant Molecular Biology, collaborating with research scientists in KAUST (Saudi Arabia). This work was published online on top-rank journal of plant biology, The Plant Cell, on Feb. 17.

Nonsense-mediated decay (NMD) is a posttranscriptional surveillance mechanism in eukaryotes that recognizes and degrades transcripts with premature translation-termination codons. This process prevents truncated proteins with potentially deleterious impacts from accumulating in cells.

The Arabidopsis thaliana FIERY2 (FRY2) locus encodes an RNA polymerase II C-terminal domain phosphatase-like protein (also called C-TERMINAL DOMAIN PHOSPHATASE-LIKE 1, CPL1). Recently, we found that FRY2 contributes to the regulation of pre-mRNA splicing and microRNA biogenesis via interacting with the KH-domain RNA binding protein HOS5 (PLoS Genetics, 2013 and Nucleic Acids Research，2015). Researchers found that FRY2/CPL1 interacts with two NMD factors, eIF4AIII and UPF3, and is involved in the dephosphorylation of eIF4AIII. This dephosphorylation retains eIF4AIII in the nucleus and limits its accumulation in the cytoplasm. The phosphorylation state of Ser-100 and Ser-101 is of critical importance in determining the nucleocytoplasmic distribution of eIF4AIII, which was further confirmed using kinase and phosphatase inhibitors. By analyzing RNA-seq data combined with quantitative RT-PCR validation, we found that a subset of alternatively spliced transcripts and 59-extended mRNAs with NMD-eliciting features accumulated in the fry2-1 mutant, cycloheximide treated wild type, and upf3 mutant plants, indicating that FRY2 is essential for the degradation of these NMD transcripts.

Dr. Tao Chen of BRI is the co-first author of this work. Dr. Chen, who is currently focusing on rice salt tolerance field in Department of Plant Molecular Biology, is the candidate of “Thousand Youth Talents Program” in 2015.

Article Link: http://www.plantcell.org/content/early/2016/02/17/tpc.15.00771.full.pdf+html