The gene coding for small ribosomal subunit RNA in the basidiomycete Ustilago maydis contains a group I intron.
The gene coding for small ribosomal subunit RNA in the basidiomycete Ustilago maydis contains a group I intron.
复制标题
担子菌玉米黑粉菌中编码小核糖体亚基 RNA 的基因包含 I 组内含子。
DOI：
10.1093/nar/20.6.1251
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发表时间：
1992
影响因子：
14.9
通讯作者：
Y. Peer
中科院分区：
文献类型：
--
作者：
R. Wachter;Jean;A. Goris;Y. Peer
测定了玉米黑粉菌核糖体小亚基RNA编码基因的核苷酸序列。它揭示了第一组内含子的存在，其长度为411个核苷酸。这是第三次在真核核基因组编码的小亚基rRNA基因中发现这样的内含子。另外两个出现在分类地位不明的真菌卡氏肺孢子虫和绿藻Ankistrodesmus stipiatus中。对存在于不同基因和基因组类型中的101组I组内含子序列的保守核心结构的核苷酸进行了比对，并检验了它们之间的进化相关性。这揭示了一个包含迄今为止在真核核基因中发现的所有I类内含子的簇，编码大小亚基rRNAs。为内含子所在的玉米黑粉菌核糖体小亚基RNA前体区域设计了二级结构模型。结果表明，与内含子边界配对的内部引导序列适合于小亚基rRNA的两个螺旋之间，最小的碱基对重排就足以在剪接时获得确定的二级结构。
The nucleotide sequence of the gene coding for small ribosomal subunit RNA in the basidiomycete Ustilago maydis was determined. It revealed the presence of a group I intron with a length of 411 nucleotides. This is the third occurrence of such an intron discovered in a small subunit rRNA gene encoded by a eukaryotic nuclear genome. The other two occurrences are in Pneumocystis carinii, a fungus of uncertain taxonomic status, and Ankistrodesmus stipitatus, a green alga. The nucleotides of the conserved core structure of 101 group I intron sequences present in different genes and genome types were aligned and their evolutionary relatedness was examined. This revealed a cluster including all group I introns hitherto found in eukaryotic nuclear genes coding for small and large subunit rRNAs. A secondary structure model was designed for the area of the Ustilago maydis small ribosomal subunit RNA precursor where the intron is situated. It shows that the internal guide sequence pairing with the intron boundaries fits between two helices of the small subunit rRNA, and that minimal rearrangement of base pairs suffices to achieve the definitive secondary structure of the 18S rRNA upon splicing.