The zinc finger protein Gsf1 regulates Gsf2‐dependent flocculation in fission yeast

Abstract Fission yeast flocculates non‐sexually by induction of the flocculin encoded by gsf2+ which is controlled by the positive regulator Mbx2. Here we report a novel gene designated gsf1+ found to be a negative regulator of non‐sexual flocculation. We identified gsf1+ as a multicopy suppressor of a sam2 mutation, which caused growth sensitivity to Ca2+ and also found a nonsense mutation in gsf1+ in a previously isolated gsf1 mutant. The gsf1+ gene encodes a 547 aa protein containing a Zn(2)‐Cys(6) binuclear cluster type Zinc finger motif. The Gsf1 protein localized in the nucleus, consistent with a role as a transcription factor. Deletion of gsf1+ resulted in non‐sexual flocculation inducible by CaCl2, which was suppressed by addition of EDTA or galactose. Both gsf2+ and mbx2+ were highly expressed in the gsf1 mutant. gsf1∆ gsf2∆ and gsf1∆ mbx2∆ double mutants did not flocculate, suggesting that gsf1+ is an upstream regulator. In addition, the gsf1 mutant was sensitive to CaCl2, KCl, HU and TBZ, consistent with the possibility that gsf1+ plays a role in functions unrelated to flocculation. Taken together, these results suggest that nonsexual flocculation in fission yeast is negatively controlled by Gsf1 which controls expression of mbx2+ and gsf2+. © 2013 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved
Source: FEMS Yeast Research - Category: Research Authors: Tags: Research Paper Source Type: research