DAL80 encodes a transcriptional repressor that is involved in negatively regulating genes that are subject to nitrogen catobolite repression (NCR) (6 and reviewed in 7). Dal80p, via a zinc finger binding domain, binds as a dimer to the URS-GATA found in the promoters of many genes involved in nitrogen utilization (6, 3). The URS-GATA consists of a pair of 5-GATAA-3 sequences separated by at least 15bp with a preferential tail to tail orientation (8). Dal80p is able to from heterodimeric complexes with Gzf3p, which may influence the DNA affinity of these proteins (3). Dal80p targets include genes involved in the import and catabolism of glutamine, glutamate, proline, urea, arginine, GABA, and allantoin, as well as genes involved in vacuolar protein degradation (6, 9, 10 and references therein).

Dal80p is one of four GATA family members which are involved in mediating nitrogen-responsive gene expression; Gln3p and Gat1p acting as activators in opposition to the Dal80p and Gzf3p repressors (reviewed in 7). Gat1p and Dal80p/Gzf3p are able to directly compete for GATA binding sites (11). Additionally, these gene products transcriptionally regulate each other and themselves in an interdependent fashion. The promoters of the GAT1, DAL80, and GZF3 genes all contain multiple GATA sequences (12, 13, 6): DAL80 expression is regulated by Gln3p, Gat1p,and Dal80p (13, 6); GAT1 expression is Gln3p and Dal80p regulated; GZF3 expression is moderately dependent on Gat1p and highly regulated by Dal80p (14). The expression levels themselves of GAT1 and DAL80 seem to regulate each other and are inversely correlated (15, 12).

Dal80p is similar to transcriptional regulators found in other fungi, birds, and mammals (16, 6). In other organisms, regulation of nitrogen metabolism may play a role in their pathogenicity (2).

Last updated: 2010-05-17