Project description:To assess the roles of the Dcp2 C-terminal domain and the decapping activators Pat1, Lsm1, and Dhh1 in mRNA decapping, we used RNA-Seq to analyze the expression profiles of yeast cells harboring a truncation of the Dcp2 C-terminal domain, mutations that render Dcp2 catalytically inactive, or deletions of the PAT1, LSM1, and DHH1 genes. Consistent with our recent model for decapping regulation, we found that: i) the Dcp2 C-terminal domain is an effector of both negative and positive regulation and that loss of these control functions causes significant deregulation of mRNA decapping; ii) rather than being global activators of decapping, Pat1, Lsm1, and Dhh1 directly target specific subsets of yeast mRNAs and loss of the functions of each of these factors has substantial indirect consequences for genome-wide mRNA expression; and iii) transcripts targeted by Pat1, Lsm1, and Dhh1 exhibit only partial overlap and, as expected, are targeted to decapping-dependent decay.
Project description:Telomere chromatin structure is pivotal for maintaining genome stability by regulating the binding of telomere-associated proteins and inhibition of a DNA damage response. In yeast, the silent information regulator (Sir) proteins bind to terminal telomeric repeats and to subtelomeric X-elements resulting in histone deacetylation and transcriptional silencing. Herein, we show that sir2 mutant strains display a very specific loss of a nucleosome residing in the X-element. Most yeast telomeres contain an X-element and the nucleosome occupancy defect in sir2 mutants is remarkably consistent between different telomeres.
