Article,
Dominant role for signal transduction in transcriptional memory of yeast GAL genes.
Molecular and cellular biology, (Mar 8, 2010)
DOI: 10.1128/mcb.01675-09
Abstract
Several recent studies have shown that transcriptional induction of yeast GAL genes occurs with faster kinetics if the gene had been previously expressed. Depending on the experimental regimen, this transcriptional "memory" phenomenon can persist for 1-2 cell divisions in the absence of inducer (short-term memory) or for >6 cell divisions (long-term memory). Long-term memory requires the GAL1 gene, suggesting that memory involves the cytoplasmic inheritance of high levels of Gal1 that are expressed in the initial round of expression. In contrast, short term memory requires the SWI/SNF chromatin remodeling enzyme, and thus it may involve inheritance of distinct chromatin states. Here we have re-evaluated the role of SWI/SNF, the histone variant H2A.Z, and components of the nuclear pore in both short-term and long-term memory of GAL genes. Our results suggest that propagation of novel chromatin structures does not contribute to transcriptional memory of GAL genes, but rather memory of the previous transcription state is primarily controlled by inheritance of the Gal3p and Gal1p signaling factors.
