Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, New York, USA.
Nat Struct Mol Biol. 2011 Jan;18(1):27-34. doi: 10.1038/nsmb.1934. Epub 2010 Dec 5.
Expression of an individual gene can vary considerably among genetically identical cells because of stochastic fluctuations in transcription. However, proteins comprising essential complexes or pathways have similar abundances and lower variability. It is not known whether coordination in the expression of subunits of essential complexes occurs at the level of transcription, mRNA abundance or protein expression. To directly measure the level of coordination in the expression of genes, we used highly sensitive fluorescence in situ hybridization (FISH) to count individual mRNAs of functionally related and unrelated genes within single Saccharomyces cerevisiae cells. Our results revealed that transcript levels of temporally induced genes are highly correlated in individual cells. In contrast, transcription of constitutive genes encoding essential subunits of complexes is not coordinated because of stochastic fluctuations. The coordination of these functional complexes therefore must occur post-transcriptionally, and likely post-translationally.
由于转录的随机波动，单个基因的表达在遗传上相同的细胞中可能会有很大差异。然而，构成必需复合物或途径的蛋白质具有相似的丰度和较低的可变性。目前尚不清楚必需复合物亚基的表达协调是否发生在转录水平、mRNA 丰度或蛋白质表达水平。为了直接测量基因表达的协调程度，我们使用高度敏感的荧光原位杂交（FISH）技术在单个酿酒酵母细胞内计数功能相关和不相关基因的单个 mRNA。我们的结果表明，单个细胞中瞬时诱导基因的转录本水平高度相关。相比之下，组成必需复合物的组成亚基的组成型基因的转录没有协调，因为存在随机波动。因此，这些功能复合物的协调必须发生在转录后，可能发生在翻译后。
