Hur M, Geese W J, Waring R B
Department of Biology, Temple University, Philadelphia, PA 19122, USA.
Curr Genet. 1997 Dec;32(6):399-407. doi: 10.1007/s002940050294.
The mitochondrial genome of Aspergillus nidulans contains several group-I introns. Each one has been assayed for its ability to self-splice in vitro in the absence of proteins. The intron from the apocytochrome b gene is unusual among subgroup IB4 introns in being able to self-splice, unlike a similar intron from Saccharomyces cerevisiae. The first intron in the cytochrome oxidase subunit-1 gene self-splices but only correctly completes the first step of splicing; cryptic 3' splice-sites are recognized instead and these are also used at a low frequency in vivo. The highly homologous intron from Podospora anserina completes both steps in vitro. The remaining introns do not self-splice. The correlation between subgroup category, the likely presence of specific tertiary interactions, and self-splicing activity is discussed.
构巢曲霉的线粒体基因组包含几个I类内含子。每个内含子都已在无蛋白质的体外条件下检测其自我剪接的能力。脱辅基细胞色素b基因的内含子在IB4亚组内含子中不同寻常，它能够自我剪接，这与酿酒酵母的类似内含子不同。细胞色素氧化酶亚基1基因中的第一个内含子能够自我剪接，但仅正确完成剪接的第一步；相反，隐蔽的3'剪接位点被识别，并且这些位点在体内也以低频率被使用。来自粪生粪壳菌的高度同源内含子在体外完成两个步骤。其余内含子不能自我剪接。本文讨论了亚组类别、特定三级相互作用的可能存在以及自我剪接活性之间的相关性。
