SOME YEAST MITOCHONDRIAL RNAS ARE CIRCULAR
SOME YEAST MITOCHONDRIAL RNAS ARE CIRCULAR
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DOI：
10.1016/0092-8674(80)90505-x
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发表时间：
1980-01-01
期刊：
影响因子：
64.5
通讯作者：
BORST, P
中科院分区：
文献类型：
--
作者：
ARNBERG, AC;VANOMMEN, GJB;BORST, P
EM检测表明，经琼脂糖凝胶电泳法分离的酵母线粒体RNA的11S和18S组分含有约50%的环状分子。11S分数中的圆的轮廓长度为0.36+-。0.02微米，大约等于大多数线性分子的长度也存在。18s分数中的圆的平均长度为0.78。+-。0.11µm。粒度分布比11S分数更宽，可能存在一个以上的尺寸类别。11S环状RNA与线粒体DNA oxi 3区的DNA片段形成环状R环，并与含有细胞色素氧化酶I亚单位结构基因的DNA片段杂交。从电子显微镜可以看出，完整的RNA参与了杂交的形成，编码它的序列显然是连续的。11S和18S环都能经受住脱氧核糖核酸酶和链霉蛋白酶的处理。它们不能用1M乙二醛在50%甲酰胺中在50度下处理1小时来消除。C.它们是共价闭合的。环状RNA的功能尚不清楚。它们可能以信使核糖核酸的形式存在，也可能以剪接的方式出现，从较长的转录本中产生信使核糖核酸。
EM examination showed that 11S and 18S fractions of yeast [Saccharomyces cerevisiae or S. carlsbergensis] mitochondrial RNA, isolated by electrophoresis through agarose gels, contain approximately 50% circular molecules. Circles in the 11S fraction have a contour length of 0.36 .+-. 0.02 .mu.m, which is approximately equal to the length of the majority of linear molecules also present. Circles in the 18S fraction have an average length of 0.78 .+-. 0.11 .mu.m. The size distribution is broader than for the 11S fraction, and it is possible that more than 1 size class may be present. The 11S circular RNA forms circular R loops and RNA-DNA hybrids with DNA fragments of the oxi 3 region of mtDNA, which contains the structural gene for subunit I of cytochrome oxidase. As judged from the electron micrographs, the complete RNA participates in hybrid formation and the sequences coding for it apparently are continuous. Both 11S and 18S circles withstand treatment with DNAse and pronase. They are not eliminated by treatment with 1 M glyoxal in 50% formamide for 1 h at 50.degree. C. They are covalently closed. The function of the circular RNA is unknown. They may be active as mRNA, storage forms, or arise in a cut-and-splice process which generates mRNA from longer transcripts.