Margossian S P, Butow R A
Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas 75235, USA.
Trends Biochem Sci. 1996 Oct;21(10):392-6.
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.
最近的证据表明，酵母线粒体中的RNA周转很重要，不仅对于调节RNA丰度很重要，而且对于促进I组内含子剪接以及抑制高水平切除的I组内含子RNA的潜在毒性作用也很重要。由于I组内含子的剪接因子与内含子RNA紧密结合，因此蛋白质辅助的I组内含子剪接要求剪接因子“主动”循环利用。推测的依赖NTP的RNA解旋酶Suv3p可能促进这种循环利用，同时抑制内含子的过度积累，因为该蛋白质与mtEXO存在功能关联，mtEXO是一种新型的3'-5'外切核糖核酸酶，能够降解切除的I组内含子RNA。
