Waksman Institute, 190 Frelinghuysen Rd., Piscataway, NJ 08854-8020, USA.
Mol Cell Biol. 2011 Apr;31(8):1701-9. doi: 10.1128/MCB.01071-10. Epub 2011 Feb 7.
Transcriptome profiling studies have recently uncovered a large number of noncoding RNA transcripts (ncRNAs) in eukaryotic organisms, and there is growing interest in their role in the cell. For example, in haploid Saccharomyces cerevisiae cells, the expression of an overlapping antisense ncRNA, referred to here as RME2 (Regulator of Meiosis 2), prevents IME4 expression. In diploid cells, the a1-α2 complex represses the transcription of RME2, allowing IME4 to be induced during meiosis. In this study we show that antisense transcription across the IME4 promoter region does not block transcription factors from binding and is not required for repression. Mutational analyses found that sequences within the IME4 open reading frame (ORF) are required for the repression mediated by RME2 transcription. These results support a model where transcription of RME2 blocks the elongation of the full-length IME4 transcript but not its initiation. We have found that another antisense transcript, called RME3, represses ZIP2 in a cell-type-specific manner. These results suggest that regulated antisense transcription may be a widespread mechanism for the control of gene expression and may account for the roles of some of the previously uncharacterized ncRNAs in yeast.
转录组谱研究最近在真核生物中发现了大量的非编码 RNA 转录本（ncRNAs），并且人们对它们在细胞中的作用越来越感兴趣。例如，在单倍体酿酒酵母细胞中，重叠的反义 ncRNA 的表达，这里称为 RME2（减数分裂 2 的调节剂），阻止了 IME4 的表达。在二倍体细胞中，a1-α2 复合物抑制 RME2 的转录，允许 IME4 在减数分裂期间被诱导。在这项研究中，我们表明跨 IME4 启动子区域的反义转录不会阻止转录因子结合，也不是抑制所必需的。突变分析发现，在 RME2 转录介导的抑制中需要 IME4 开放阅读框（ORF）内的序列。这些结果支持这样一种模型，即 RME2 的转录阻止全长 IME4 转录物的延伸，但不阻止其起始。我们发现另一种称为 RME3 的反义转录本以细胞类型特异性的方式抑制 ZIP2。这些结果表明，受调控的反义转录可能是控制基因表达的一种广泛机制，并可能解释了一些以前未被表征的 ncRNA 在酵母中的作用。
