Polyadenylation accelerates the degradation of the mitochondrial mRNA associated with cytoplasmic male sterility in sunflower

• Published in: The EMBO journal 1999-07, Vol.18 (13), p.3757-3766
• Main Authors: Gagliardi, D, Leaver, C.J
• Format: Article
• Language: English
• Subjects: 3' Untranslated Regions - genetics; adenosinetriphosphatase; atpa gene; Base Sequence; Cell Nucleus - genetics; chemical reactions; Chimera - genetics; cotyledons; Cytoplasm - genetics; cytoplasmic male sterility; degradation; Fertility; flowers; Gene Expression Regulation, Plant; genes; Genes, Plant - genetics; genomics; Helianthus - cytology; Helianthus - genetics; Helianthus - physiology; Helianthus annuus; Kinetics; male florets; Male sterility; messenger RNA; Mitochondria - enzymology; Mitochondria - genetics; mitochondrial DNA; open reading frames; Open Reading Frames - genetics; Organ Specificity; plant mitochondria; Plant Structures - genetics; Poly A - metabolism; polyadenylation; ribonucleases; Ribonucleases - isolation & purification; Ribonucleases - metabolism; RNA degradation; RNA Processing, Post-Transcriptional; RNA, Messenger - genetics; RNA, Messenger - metabolism; Solanum tuberosum - enzymology; Substrate Specificity; sunflower
• ISSN: 0261-4189; 1460-2075; 1460-2075
• DOI: 10.1093/emboj/18.13.3757

In sunflower, PET1‐cytoplasmic male sterility is correlated with the presence of a novel mitochondrial gene ( orf522 ) located 3′ to the atpA gene. The dicistronic atpA‐orf522 transcripts are preferentially destabilized in male florets of ‘restored to fertility’ plants as compared with sterile plants. In this report, we show that atpA‐orf522 transcripts may be polyadenylated in vivo at their 3′ termini and that a tissue‐specific increase in the level of polyadenylated atpA‐orf522 transcripts correlates with the tissue‐specific instability of atpA‐orf522 mRNAs in male florets of the restored hybrid plants. In addition, we have identified two distinct ribonuclease activities in sunflower mitochondria, one of which preferentially degrades polyadenylated as compared with non‐polyadenylated RNA substrates corresponding to the 3′ UTR of atpA‐orf522 transcripts. These in vivo and in vitro results show that polyadenylation is involved in the degradation pathway of the mitochondrial atpA‐orf522 transcripts and that polyadenylation can be developmentally regulated by a nuclear gene(s) upon restoration of fertility.