Systematic genetic array analysis links the Saccharomyces cerevisiae SAGA/SLIK and NuA4 component Tra1 to multiple cellular processes.
BACKGROUND
Tra1 is an essential 437-kDa component of the Saccharomyces cerevisiae SAGA/SLIK and NuA4 histone acetyltransferase complexes. It is a member of a group of key signaling molecules that share a carboxyl-terminal domain related to phosphatidylinositol-3-kinase but unlike many family members, it lacks kinase activity. To identify genetic interactions for TRA1 and provide insight into its function we have performed a systematic genetic array analysis (SGA) on tra1SRR3413, an allele that is defective in transcriptional regulation.


RESULTS
The SGA analysis revealed 114 synthetic slow growth/lethal (SSL) interactions for tra1SRR3413. The interacting genes are involved in a range of cellular processes including gene expression, mitochondrial function, and membrane sorting/protein trafficking. In addition many of the genes have roles in the cellular response to stress. A hierarchal cluster analysis revealed that the pattern of SSL interactions for tra1SRR3413 most closely resembles deletions of a group of regulatory GTPases required for membrane sorting/protein trafficking. Consistent with a role for Tra1 in cellular stress, the tra1SRR3413 strain was sensitive to rapamycin. In addition, calcofluor white sensitivity of the strain was enhanced by the protein kinase inhibitor staurosporine, a phenotype shared with the Ada components of the SAGA/SLIK complex. Through analysis of a GFP-Tra1 fusion we show that Tra1 is principally localized to the nucleus.


CONCLUSIONS
We have demonstrated a genetic association of Tra1 with nuclear, mitochondrial and membrane processes. The identity of the SSL genes also connects Tra1 with cellular stress, a result confirmed by the sensitivity of the tra1SRR3413 strain to a variety of stress conditions. Based upon the nuclear localization of GFP-Tra1 and the finding that deletion of the Ada components of the SAGA complex result in similar phenotypes as tra1SRR3413, we suggest that the effects of tra1SRR3413 are mediated, at least in part, through its role in the SAGA complex.
Hoke
Stephen M T
SM
Department of Biochemistry, Schulich School of Medicine & Dentistry, University of Western Ontario, London, N6A 5C1, Canada. shoke@uwo.ca
Guzzo
Julie
J
Andrews
Brenda
B
Brandl
Christopher J
CJ
D000483:Alleles; D001557:Benzenesulfonates / Q000494:pharmacology; D002467:Cell Nucleus / Q000235:genetics; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D008040:Genetic Linkage; D049452:Green Fluorescent Proteins; D051548:Histone Acetyltransferases / Q000235:genetics; D007425:Intracellular Membranes / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D010957:Plasmids; D021381:Protein Transport; D011993:Recombinant Fusion Proteins / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism*; D017384:Sequence Deletion; D013012:Sorbitol / Q000494:pharmacology; D019311:Staurosporine / Q000494:pharmacology; D015534:Trans-Activators / Q000235:genetics
D001557:Benzenesulfonates; D011993:Recombinant Fusion Proteins; C507785:SAGA complex, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C491364:TRA1 protein, S cerevisiae; D015534:Trans-Activators; D049452:Green Fluorescent Proteins; D013012:Sorbitol; C007061:C.I. Fluorescent Brightening Agent 28; D051548:Histone Acetyltransferases; C504740:NuA4 protein, S cerevisiae; D019311:Staurosporine