Initiation of the yeast G0 program requires Igo1 and Igo2, which antagonize activation of decapping of specific nutrient-regulated mRNAs.

Growth factors and essential nutrients are key controllers of eukaryotic cell proliferation. In their absence, cells may enter into a quiescent (G0) state. In yeast, nitrogen and/or carbon limitation causes downregulation of the conserved TORC1 and PKA signaling pathways and consequently activation of Rim15, a member of the PAS protein kinase family. Rim15 orchestrates the initiation of the G0 program in part by coordinating transcription of Msn2/4- and/or Gis1-dependent genes with posttranscriptional protection of the corresponding mRNAs via direct phosphorylation of Igo1/2. Here, we show that several factors including Ccr4, the Lsm-Pat1 complex, and Dhh1, which are implicated in mRNA decapping activation, participate in the decay of specific mRNAs during initiation of the G0 program when Igo1/2 are absent. Accordingly, Igo1/2 likely play a key role in preventing the decapping and subsequent 5'-3' degradation of a set of nutrient-regulated mRNAs that are critical for cell differentiation and chronological life span.

Citation

Xuan Luo, Nicolas Talarek, Claudio De Virgilio. Initiation of the yeast G0 program requires Igo1 and Igo2, which antagonize activation of decapping of specific nutrient-regulated mRNAs. RNA biology. 2011 Jan-Feb;8(1):14-7

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PMID: 21289492

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