Promoter sequences regulated by the calcineurin-activated transcription factor Crz1 in the yeast ENA1 gene

In Saccharomyces cerevisiae the transcription of the ENA1 gene is modulated by multiple transduction pathways that respond to osmotic, ionic and nutri ent stresses. We have investigated the molecular mechanisms involved in ENA 1 induction by the calcium-calcineurin-activated transcription factor Crz1/ Tcn1. We found in the ENA1 promoter a calcium-responsive, Crz1-dependent up stream activating region (UAS(ENA1)) located between -713 bp and -826 bp re lative to the translation start. This region contains two separate control elements: the upstream element (5 ' -GAATGGCTG-3 ') between -813 and -821 b inds Crz1p with lower affinity and mostly contributes to basal ENA1 express ion, whereas the downstream element (5 ' -GGGTGGCTG-3 ') between -727 and - 719 binds Crz1p with higher affinity and is a major determinant of the indu ction response to calcium.