The Yeast GATA Factor Gat1 Occupies a Central Position in Nitrogen Catabolite Repression-Sensitive Gene Activation

Institut de Recherches Microbiologiques J.-M. Wiame, Laboratoire de Microbiologie, Université Libre de Bruxelles, Av. E. Gryson 1, B-1070 Bruxelles, Belgium.
Molecular and Cellular Biology (Impact Factor: 4.78). 05/2009; 29(13):3803-15. DOI: 10.1128/MCB.00399-09
Source: PubMed


Saccharomyces cerevisiae cells are able to adapt their metabolism according to the quality of the nitrogen sources available in the environment. Nitrogen
catabolite repression (NCR) restrains the yeast's capacity to use poor nitrogen sources when rich ones are available. NCR-sensitive
expression is modulated by the synchronized action of four DNA-binding GATA factors. Although the first identified GATA factor,
Gln3, was considered the major activator of NCR-sensitive gene expression, our work positions Gat1 as a key factor for the
integrated control of NCR in yeast for the following reasons: (i) Gat1 appeared to be the limiting factor for NCR gene expression,
(ii) GAT1 expression was regulated by the four GATA factors in response to nitrogen availability, (iii) the two negative GATA factors
Dal80 and Gzf3 interfered with Gat1 binding to DNA, and (iv) Gln3 binding to some NCR promoters required Gat1. Our study also
provides mechanistic insights into the mode of action of the two negative GATA factors. Gzf3 interfered with Gat1 by nuclear
sequestration and by competition at its own promoter. Dal80-dependent repression of NCR-sensitive gene expression occurred
at three possible levels: Dal80 represses GAT1 expression, it competes with Gat1 for binding, and it directly represses NCR gene transcription.

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Available from: Isabelle Georis
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    • "Fig. 6a). Deletion of GZF3 does, however, result in increased expression for a second activator Gat1[50], as well as two other GATA regulated genes MEP2 and DAL3[47,51](Fig. 6c; Fig. 6d, gzf3Δ panel). "
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    • "The different subcellular fractions were analyzed by Western blotting with monoclonal antibodies for c-Myc (Santa Cruz Biotechnology), Pep12 (Invitrogen) and Pgk1 (Invitrogen, Carlsbad, CA). The electrophoresis, blotting, and detection procedures have been described previously (Georis et al. 2009). "
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