Ito Takashi, Miura Fumihito, Onda Miyuki
Department of Computational Biology, Graduate School of Frontier Sciences, University of Tokyo, Kashiwa 277-8561, Japan.
IUBMB Life. 2008 Dec;60(12):775-81. doi: 10.1002/iub.121.
The genome of the budding yeast Saccharomyces cerevisiae was sequenced over a decade ago and has been annotated to encode approximately 6,000 genes. However, recent high throughput studies using tiling array hybridization and cDNA sequencing have revealed an unexpectedly large number of previously undescribed transcripts. They largely lack protein-coding capacity and are transcribed from both strands of intragenic and intergenic regions in the genome. Accordingly, pervasive transcription leading to a plethora of noncoding RNAs, which was first revealed for mammalian genomes to attract intense attentions, is likely an intrinsic feature of eukaryotic genomes. Although it is not clear what fraction of these transcription events are functional, some were shown to induce transcriptional interference or histone modifications to regulate gene expression. The budding yeast may serve as an excellent model to study pervasive transcription and noncoding RNAs.
十多年前，就已完成了出芽酵母酿酒酵母的基因组测序，其注释显示该基因组编码约6000个基因。然而，最近利用平铺阵列杂交和cDNA测序进行的高通量研究发现了数量惊人的此前未被描述的转录本。它们大多缺乏蛋白质编码能力，且从基因组内基因区和基因间区的两条链转录而来。因此，普遍转录导致大量非编码RNA的产生，这一现象最初在哺乳动物基因组中被发现并引起了广泛关注，它可能是真核生物基因组的一个固有特征。尽管尚不清楚这些转录事件中有多少具有功能，但已有研究表明，一些转录事件可诱导转录干扰或组蛋白修饰来调控基因表达。出芽酵母可能是研究普遍转录和非编码RNA的理想模型。
