Crosstalk between RNA silencing and RNA quality control in plants

Abstract

RNAs are pivotal molecules acting as messengers of genetic information and regulatory molecules for cellular development and survival. From birth to death, RNAs face constant cellular decision for the precise control of cellular function and activity. Most eukaryotic cells employ conserved machineries for RNA decay including RNA silencing and RNA quality control (RQC). In plants, RQC monitors endogenous RNAs and degrades aberrant and dysfunctional species, whereas RNA silencing promotes RNA degradation to repress the expression of selected endogenous RNAs or exogenous RNA derived from transgenes and virus. Interestingly, emerging evidences have indicated that RQC and RNA silencing interact with each by sharing target RNAs and regulatory components. Such interaction should be tightly organized for proper cellular survival. However, it is still elusive that how each machinery specifically recognizes target RNAs. In this review, we summarize recent advances on RNA silencing and RQC pathway and discuss potential mechanisms underlying the interaction between the two machineries. [BMB Reports 2023; 56(6): 321-325].

Fig. 1

RNA degradation processes controlled by the RNA quality control and the RNA silencing pathways. RNA degradation processes targeted by the RNA quality control and the RNA silencing pathways and their interaction. The RQC pathway degrades aberrant RNAs such as decapped and/or deadenylated transcripts through exonuclease activities. Exogenous and a portion of endogenous RNAs enter to the RNA silencing pathway by the production of RDR6-dependent siRNAs. The siRNAs are loaded onto AGO1 and facilitate mRNA cleavage. The RQC pathway eliminates aberrant RNAs via mRNA deadenylation and decapping-dependent bidirectional degradation. The RQC pathway suppresses RNA silencing. When the RQC pathway does not operate properly, the accumulated RNAs are served as substrates for RDR6, which turns on RNA silencing. Meanwhile, RPT2a, a subunit of 26S proteasome complex, attenuates the RQC pathway, resulting enforced RNA silencing, which suggests that the two pathways might have more dynamic bidirectional antagonistic interaction depending on the situation.