Originally published as Genetics Published Articles Ahead of Print on June 29, 2009.

Genetics, Vol. 183, 185-194, September 2009, Copyright © 2009
doi:10.1534/genetics.109.105155

Alternative Splicing of PTC7 in Saccharomyces cerevisiae Determines Protein Localization

Kara Juneau*,1, Corey Nislow{dagger} and Ronald W. Davis*

* Stanford Genome Technology Center, Department of Biochemistry, Stanford University School of Medicine, Palo Alto, California 94304 and {dagger} Banting and Best Department of Medical Research, Department of Molecular Genetics, Donnelley Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario M5S 3E1, Canada

1 Corresponding author: Stanford Genome Technology Center, Department of Biochemistry, Stanford University School of Medicine, 855 California Ave., Palo Alto, California 94304.
E-mail: kjuneau{at}stanford.edu

It is well established that higher eukaryotes use alternative splicing to increase proteome complexity. In contrast, Saccharomyces cerevisiae, a single-cell eukaryote, conducts predominantly regulated splicing through retention of nonfunctional introns. In this article we describe our discovery of a functional intron in the PTC7 (YHR076W) gene that can be alternatively spliced to create two mRNAs that code for distinct proteins. These two proteins localize to different cellular compartments and have distinct cellular roles. The protein translated from the spliced mRNA localizes to the mitochondria and its expression is carbon-source dependent. In comparison, the protein translated from the unspliced mRNA contains a transmembrane domain, localizes to the nuclear envelope, and mediates the toxic effects of Latrunculin A exposure. In conclusion, we identified a definitive example of functional alternative splicing in S. cerevisiae that confers a measurable fitness benefit.


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Genetics 2009 183: NP. [Full Text]