Poster abstracts
Poster number 11 submitted by Stevin Wilson
Understanding zinc sensing mechanism in S. pombe
Stevin Wilson (Dept. of Molecular Genetics), Amanda J. Bird (Dept. of Human Sciences, Dept. of Molecular Genetics, Center for RNA Biology)
Abstract:
Metalloproteins constitute one-third of the proteome. A subset of these proteins, including numerous transcription factors and enzymes that bind the essential metal zinc. According to the Irving Williams Series, complexes formed with zinc have the highest stability among transition metals with the exception of copper. Thus, in excess, zinc can cause mismetallation resulting in non-functioning or even toxic metalloprotein complexes. To maintain a species-specific optimum range of zinc concentration, many organisms use zinc-responsive transcription factors to control the expression of genes required for zinc uptake, storage, and efflux. To understand how eukaryotic cells sense and maintain zinc homeostasis, we use Schizosaccharomyces pombe as model system. In S. pombe, Loz1 is a transcription repressor that is required for zinc-dependent regulation. However, it is not yet known whether Loz1 activity is directly regulated by zinc or whether Loz1 is a single component of a larger zinc-sensing pathway. In my studies I am using multiple approaches to determine how Loz1 senses zinc. In a recent publication, zinc-dependent regulation of two Loz1 target genes was reported to be lost in ecl1/2/3 triple knockout strains (Ohtsuka et.al 2014). The ecl (extension of chronological lifespan) genes encode proteins of unknown function that contain a putative zinc binding motif at their extreme N-terminus. Using multiple genetic approaches, I tested whether the Ecl proteins control Loz1 activity. As an unbiased approach, I am also using a proximity-dependent biotin identification system (BioID) to determine whether any additional proteins interact with Loz1. The results from both of these studies will be discussed.
Keywords: Zinc Homeostasis, Yeast, Transcription factor