A poly(A)-specific ribonuclease directly regulates the poly(A) status of mitochondrial mRNA in Arabidopsis

Abstract

Coordination of gene expression in the organelles and the nucleus is important for eukaryotic cell function. Transcriptional and post-transcriptional gene regulation in mitochondria remains incompletely understood in most eukaryotes, including plants. Here we show that poly(A)-specific ribonuclease, which influences the poly(A) status of cytoplasmic mRNA in many eukaryotes, directly regulates the poly(A) tract of mitochondrial mRNA in conjunction with a bacterial-type poly(A) polymerase, AGS1, in Arabidopsis. An Arabidopsis poly(A)-specific ribonuclease-deficient mutant, ahg2-1, accumulates polyadenylated mitochondrial mRNA and shows defects in mitochondrial protein complex levels. Mutations of AGS1 suppress the ahg2-1 phenotype. Mitochondrial localizations of AHG2 and AGS1 are required for their functions in the regulation of the poly(A) tract of mitochondrial mRNA. Our findings suggest that AHG2 and AGS1 constitute a regulatory system that controls mitochondrial mRNA poly(A) status in Arabidopsis.

Abscisic acid induces ectopic outgrowth in epidermal cells through cortical microtubule reorganization in Arabidopsis thaliana

“…Next, we analyzed the effect of ABA on epidermal cells in aba hypersensitive germination ( ahg ) mutants, which show a hypersensitivity to ABA during germination and early seedling growth414243444546. The ahg1-1 , ahg2-1 and ahg3-1 mutants grown in the presence of ABA exhibited enhanced ectopic outgrowth and produced larger numbers of protrusions than the wild type (Fig.…”

“…In addition, the specific function of AHG1 and AHG3 in seed germination and early growth is well correlated with the requirement of ABA during germination and the early phase of seedling growth for ectopic outgrowth to occur. AHG2 encodes the polyA-specific ribonuclease (PARN) that modulates ABA and salicylic acid signaling via mitochondrial RNA metabolism424546. The PP2Cs and AHG2-dependent pathway might be coordinately involved in ABA-dependent ectopic outgrowth in epidermal cells.…”

“…The mutants of abi1-1 , abi2-1 , abi4-1 , abi5-1 , ahg1-1 , ahg2-1 and ahg3-1 were described previously414243444546. The mutants of ktn1 P393S , tua4 S178δ , phs1-1 , spr1-3 and spr2-2 and GFP-TUB6 line were described previously89101112134951.…”

DsCaf1 is involved in environmental stress response of Dunaliella salina

“…Nonetheless, several previous studies have clearly shown that deadenylases are required for the development and stress response of plants. For example in Arabidopsis thaliana, PARN is essential for embryogenesis [6,7], response to abscisic acid and salicylic acid [8,9] as well as mitochondrion functions [10]. Caf1 is involved in the responses to both biotic and abiotic stresses in Capsicum annuum, Arabidopsis thaliana and Oryza sativa [11][12][13][14].…”

A unique system for regulating mitochondrial mRNA poly(A) status and stability in plants

“…1 This necessitates tightly coordinated gene expression between the nuclear and organellar genomes. 8 This finding is surprising given that PARN is distributed widely among eukaryotes (other than budding yeast and Drosophila 9 ) and has been shown to regulate the poly(A) status of cytoplasmic RNA in various organisms, but never in organelles. [2][3][4] Although neither signaling system has been fully elucidated, they are thought to involve regulation at the levels of transcription, post-transcription, and post-translation, in both the nucleus and organelles.…”