Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.13.1 (exoribonuclease)
 732 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The yeast mitochondrial protein Suv3p is a putative NTP-dependent RNA helicase. Here we report that in cells lacking Suv3p, there is an approximately 50-fold increase in the excised form of the group I intron omega of the mitochondrial 31S rRNA gene. Surprisingly, little mature 21S rRNA accumulates in those cells; instead, unligated 21S rRNA exons appear. Intron overaccumulation could lead to spliced exon reopening via a reaction known to be catalyzed by group I introns in vitro. We also show that Suv3p is a functional component of a novel mitochondrial NTP-dependent 3'-to-5' exoribonuclease activity that can degrade group I intron RNAs. These findings account for group I intron overaccumulation in cells lacking Suv3p and define a novel function for putative RNA helicases in direct RNA degradation.
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PMID:The DExH box protein Suv3p is a component of a yeast mitochondrial 3'-to-5' exoribonuclease that suppresses group I intron toxicity. 856 66

Recent evidence suggests that RNA turnover in yeast mitochondria is important, not only to regulate RNA abundance, but also to facilitate group I intron splicing and suppress the potentially toxic effect of high levels of excised group I intron RNAs. Protein-assisted splicing of group I introns requires that splicing factors are 'actively' recycled, because of their tight binding to the intron RNA. The putative NTP-dependent RNA helicase Suv3p might promote this recycling and, at the same time, suppress intron overaccumulation because of the functional association of this protein with mtEXO, a novel 3'-5' exoribonuclease that can degrade excised group I intron RNAs.
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PMID:RNA turnover and the control of mitochondrial gene expression. 891 94

The yeast mitochondrial degradosome (mtEXO) is an NTP-dependent exoribonuclease involved in mitochondrial RNA metabolism. Previous purifications suggested that it was composed of three subunits. Our results suggest that the degradosome is composed of only two large subunits: an RNase and a RNA helicase encoded by nuclear genes DSS1 and SUV3, respectively, and that it co-purifies with mitochondrial ribosomes. We have found that the purified degradosome has RNA helicase activity that precedes and is essential for exoribonuclease activity of this complex. The degradosome RNase activity is necessary for mitochondrial biogenesis but in vitro the degradosome without RNase activity is still able to unwind RNA. In yeast strains lacking degradosome components there is a strong accumulation of mitochondrial mRNA and rRNA precursors not processed at 3'- and 5'-ends. The observed accumulation of precursors is probably the result of lack of degradation rather than direct inhibition of processing. We suggest that the degradosome is a central part of a mitochondrial RNA surveillance system responsible for degradation of aberrant and unprocessed RNAs.
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PMID:The yeast mitochondrial degradosome. Its composition, interplay between RNA helicase and RNase activities and the role in mitochondrial RNA metabolism. 1242 13