Transcription of functionally related constitutive genes is not coordinated

Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, New York, USA.
Nature Structural & Molecular Biology (Impact Factor: 13.31). 01/2011; 18(1):27-34. DOI: 10.1038/nsmb.1934
Source: PubMed


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.

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