The Long Intergenic Noncoding RNA ARTA Specifically Regulates MYB7 Nuclear Trafficking to Establish a Self-Reinforcing Circuit for ABA Response.

Long noncoding RNAs are involved in diverse biological processes in plants. Our recent study has revealed that an ABA-induced long intergenic noncoding RNA, ARTA, regulates both ABA and drought responses by blocking the nuclear import of a transcription factor, MYB7, through interacting with an importin β-like protein, SAD2. Here, we show that unlike MYB7, ARTA fails to disrupt interactions of SAD2 with the other two R2R3-MYB subgroup 4 members, MYB4 and MYB32. Consequently, the nuclear localizations of MYB4 and MYB32 remain unchanged upon alteration of ARTA expression. Furthermore, ARTA and MYB7 form a self-reinforcing feedback loop during Arabidopsis responses to ABA: ABA treatment induces ARTA expression, which in turn inhibits nuclear accumulation of MYB7, thereby deteriorating MYB7-mediated repression of ARTA and promoting ARTA production. This self-reinforcing feedback regulation elegantly integrates protein relocalization with transcriptional augmentation in the ABA response process, and provides a tunable molecular circuit for plant stress adaptation.