N-methyladenosine on the natural antisense transcript of NIA1 stabilizes its mRNA to boost NO biosynthesis and modulate stomatal movement

Le résumé fourni par la source

Nitric oxide (NO) is a crucial signaling molecule that regulates a wide range of metabolic pathways in different strata of organisms. In plants, nitrate reductase (NR) is a key enzyme for NO biosynthesis. There are two NR-encoding genes in Arabidopsis genome, NIA1 and NIA2 , which are precisely regulated and expressed in a tissue-specific manner. In this study, we found that the natural antisense transcript as- NIA1 , transcribed from the 3′ UTR of NIA1 , stabilizes NIA1 mRNA to maintain its circadian oscillation in plants grown under the light/dark cycle. Importantly, as- NIA1 -dependent NIA1 mRNA stability is indispensable for NIA1-mediated NO biosynthesis in guard cells and natural stomatal closure. Moreover, we revealed that polypyrimidine tract-binding 3 (PTB3) regulates the stabilization of NIA1 mRNA by directly binding to UC-rich elements of as- NIA1 . We further found that MTA deposits N 6 -methyladenosine (m 6 A) on as- NIA1 , facilitating the as- NIA1 -PTB3 interaction in vivo , in agreement with RNA structure prediction in that m 6 A-mediated structural alterations expose the UC-rich elements to enhance the accessibility of PTB3. Taken together, these findings reveal a novel molecular mechanism by which plants precisely manipulate NO biosynthesis to modulate light/dark-regulated stomatal movement, highlighting the coupling of RNA epigenetic modifications and structures shaping RNA-protein interactions in the regulation of hormone biosynthesis.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.