Different physiological relevance of yeast THO/TREX subunits in gene expression and genome integrity.
THO/TREX is a conserved nuclear complex that functions in mRNP biogenesis and plays a role in preventing the transcription-associated genetic instability. THO is composed of Tho2, Hpr1, Mft1 and Thp2 subunits, which associate with the Sub2-Yra1 export factors and Tex1 to form the TREX complex. To compare the functional relevance of the different THO/TREX subunits, we determined the effect of their null mutations on mRNA accumulation and recombination. Unexpectedly, we noticed that a full deletion of HPR1, hpr1DeltaK, conferred stronger hyper-recombination phenotype and gene expression defects than did hpr1DeltaH, the allele encoding a C-terminal truncated protein which was used in most previous studies. We show that tho2Delta and, to a lesser extent, hpr1DeltaK are the THO mutations with the highest impact on all phenotypes, and that sub2Delta shows a similar transcription-dependent hyper-recombination phenotype and in vivo transcription impairment as hpr1DeltaK and tho2Delta. Recombination and transcription analyses indicate that THO/TREX mutants share a moderate but significant effect on gene conversion and ectopic recombination, as well as transcription impairment of even short and low GC-content genes. Our data provide new information on the relevance of these proteins in mRNP biogenesis and in the maintenance of genomic integrity.
García-Rubio
María
M
Departamento de Biología Molecular, CABIMER, CSIC, Universidad de Sevilla, Av. Américo Vespucio s/n, Seville, Spain.
Chávez
Sebastián
S
Huertas
Pablo
P
Tous
Cristina
C
Jimeno
Sonia
S
Luna
Rosa
R
Aguilera
Andrés
A
D000483:Alleles; D015152:Blotting, Northern; D002352:Carrier Proteins / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D015825:Chromosomes, Fungal / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D015966:Gene Expression Regulation, Fungal; D016681:Genome, Fungal; D008957:Models, Genetic; D009154:Mutation; D010641:Phenotype; D010957:Plasmids / Q000235:genetics; D021122:Protein Subunits / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011995:Recombination, Genetic; D012261:Ribonucleoproteins / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D014158:Transcription, Genetic
D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D021122:Protein Subunits; D012333:RNA, Messenger; D012261:Ribonucleoproteins; D029701:Saccharomyces cerevisiae Proteins; C000602623:Tex1 protein, S cerevisiae; C462947:Thp2 protein, S cerevisiae; C026452:messenger ribonucleoprotein