HOG1 papers

HOG1 papers

Postby DNAer » Thu Mar 07, 2013 1:12 pm

Coordinated control of replication and transcription by a SAPK protects genomic integrity.
Duch A, Felipe-Abrio I, Barroso S, Yaakov G, García-Rubio M, Aguilera A, de Nadal E, Posas F.
Nature. 2013 Jan 3;493(7430):116-9

Upon environmental changes or extracellular signals, cells are subjected to marked changes in gene expression. Dealing with high levels of transcription during replication is critical to prevent collisions between the transcription and replication pathways and avoid recombination events. In response to osmostress, hundreds of stress-responsive genes are rapidly induced by the stress-activated protein kinase (SAPK) Hog1 (ref. 6), even during S phase. Here we show in Saccharomyces cerevisae that a single signalling molecule, Hog1, coordinates both replication and transcription upon osmostress. Hog1 interacts with and phosphorylates Mrc1, a component of the replication complex. Phosphorylation occurs at different sites to those targeted by Mec1 upon DNA damage. Mrc1 phosphorylation by Hog1 delays early and late origin firing by preventing Cdc45 loading, as well as slowing down replication-complex progression. Regulation of Mrc1 by Hog1 is completely independent of Mec1 and Rad53. Cells carrying a non-phosphorylatable allele of MRC1 (mrc1(3A)) do not delay replication upon stress and show a marked increase in transcription-associated recombination, genomic instability and Rad52 foci. In contrast, mrc1(3A) induces Rad53 and survival in the presence of hydroxyurea or methyl methanesulphonate. Therefore, Hog1 and Mrc1 define a novel S-phase checkpoint independent of the DNA-damage checkpoint that permits eukaryotic cells to prevent conflicts between DNA replication and transcription, which would otherwise lead to genomic instability when both phenomena are temporally coincident.

PMID: 23178807

http://www.ncbi.nlm.nih.gov/pubmed/23178807
User avatar
DNAer
 
Posts: 20
Joined: Tue Aug 16, 2011 5:35 pm
Location: Leipzig

Re: HOG1 papers

Postby DNAer » Thu Mar 07, 2013 1:15 pm

Hog1 controls global reallocation of RNA Pol II upon osmotic shock in Saccharomyces cerevisiae.

Cook KE, O'Shea EK.

G3 (Bethesda). 2012 Sep;2(9):1129-36


When challenged with osmotic shock, Saccharomyces cerevisiae induces hundreds of genes, despite a concurrent reduction in overall transcriptional capacity. The stress-responsive MAP kinase Hog1 activates expression of specific genes through interactions with chromatin remodeling enzymes, transcription factors, and RNA polymerase II. However, it is not clear whether Hog1 is involved more globally in modulating the cell's transcriptional program during stress, in addition to activating specific genes. Here we show that large-scale redistribution of RNA Pol II from housekeeping to stress genes requires Hog1. We demonstrate that decreased RNA Pol II occupancy is the default outcome for highly expressed genes upon stress and that Hog1 is partially required for this effect. We find that Hog1 and RNA Pol II colocalize to open reading frames that bypass global transcriptional repression. These activation targets are specified by promoter binding of two osmotic stress-responsive transcription factors. The combination of reduced global transcription with a gene-specific override mechanism allows cells to rapidly switch their transcriptional program in response to stress.

PMID: 22973550

http://www.ncbi.nlm.nih.gov/pubmed/22973550
User avatar
DNAer
 
Posts: 20
Joined: Tue Aug 16, 2011 5:35 pm
Location: Leipzig


Return to Literature recommendations

Who is online

Users browsing this forum: No registered users and 1 guest

cron