Sporulation-specific expression of the yeast DIT1/DIT2 promoter is controlled by a newly identified repressor element and the short form of Rim101p

Expression of the yeast genes DIT1 and DIT2 is confined to mid/late sporula tion, Transcription of these two divergently arranged genes is controlled b y a common 900-bp intergenic region. Random mutagenesis of this promoter an d tests with appropriate reporter constructs identified an 11-bp cis-acting palindromic sequence, DIT repressor element (DRE), as a major negative reg ulatory site during vegetative growth. Repression is exerted by DRE in conj unction with a mid-sporulation element (MSE)-like sequence situated 26 bp a way. These sequence elements are both contained within the 76-bp negative r egulatory element (NRE) defined previously [Friesen H., Hepworth, S. R. & S egall, J. (1997) Mol. Cell. Biol. 17, 123-134]. The activated form of Rim10 1p, a transcriptional inducer of the early meiotic gene lMEl, enhances expr ession from the DIT1 promoter both in vegetative and sporulating cells. Act ivation by Rim101p does not seem to involve binding of Rim101p at either of the two cis-acting sites described here, since reporter constructs with bo th elements or most of the NRE deleted could still be activated by the: Sho rt form Of Rim101p.