Genome-wide analyses of two families of snoRNA genes from Drosophila melanogaster, demonstrating the extensive utilization of introns for coding of snoRNAs
Genome-wide analyses of two families of snoRNA genes from Drosophila melanogaster, demonstrating the extensive utilization of introns for coding of snoRNAs
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作者：
Huang, ZP;Zhou, H;Qu, LH
核仁小RNA（snoRNAs）是一类丰富的非编码RNA，主要参与真核生物中核糖体RNA（rRNAs）的转录后修饰。在这项研究中，利用实验和计算核糖核酸组学方法对果蝇（Drosophila melanogaster）中两个主要的snoRNA基因家族进行了大规模的全基因组分析。鉴定出212个基因变体，编码56个H/ACA框和63个C/D框snoRNAs，其中57个新的snoRNAs首次被报道。这些snoRNAs预计可引导对rRNAs和核小RNA（snRNAs）总共147次甲基化和假尿苷酸化，显示出果蝇中rRNA修饰的更全面模式。除了9个之外，迄今为止在果蝇中鉴定出的所有snoRNAs都是内含子编码的。值得注意的是，snoRNAs的基因组组织具有8个dUhg基因和17个内含子基因簇的特征，这表明不同的组织形式主导着果蝇中两个snoRNA家族的表达。在宿主基因的267个内含子中，超过一半已被确定为编码snoRNAs的宿主内含子。与哺乳动物不同，宿主内含子大小的变化主要是由于它们所包含的snoRNAs数量不同。这些结果表明宿主基因中内含子被广泛用于编码snoRNAs，并为进一步研究果蝇基因组大内含子中的其他非编码RNA基因提供了启示。
Small nucleolar RNAs (snoRNAs) are an abundant group of noncoding RNAs mainly involved in the post-transcriptional modifications of rRNAs in eukaryotes. In this study, a large-scale genome-wide analysis of the two major families of snoRNA genes in the fruit fly Drosophila melanogaster has been performed using experimental and computational RNomics methods. Two hundred and twelve gene variants, encoding 56 box H/ACA and 63 box C/D snoRNAs, were identified, of which 57 novel snoRNAs have been reported for the first time. These snoRNAs were predicted to guide a total of 147 methylations and pseudouridylations on rRNAs and snRNAs, showing a more comprehensive pattern of rRNA modification in the fruit fly. With the exception of nine, all the snoRNAs identified to date in D. melanogaster are intron encoded. Remarkably, the genomic organization of the snoRNAs is characteristic of 8 dUhg genes and 17 intronic gene clusters, demonstrating that distinct organizations dominate the expression of the two families of snoRNAs in the fruit fly. Of the 267 introns in the host genes, more than half have been identified as host introns for coding of snoRNAs. In contrast to mammals, the variation in size of the host introns is mainly due to differences in the number of snoRNAs they contain. These results demonstrate the extensive utilization of introns for coding of snoRNAs in the host genes and shed light on further research of other noncoding RNA genes in the large introns of the Drosophila genome.