A temperature-sensitive lambda cI repressor functions on a modified operator in yeast cells by masking the TATA element.

We describe the construction and analysis of derivatives of the yeast TDH3 promoter in which the TATA box element has been replaced by a portion of the phage lambda operator containing a consensus TATA site flanked by binding sites for the cI repressor. Transcription of a reporter gene under the control of such a promoter is reduced in cells that express the cI repressor protein. Deletion of the native TATA element of the TDH3 promoter reduces transcription to the same extent. The cI repressor may act by "masking" the TATA element located between the repressor binding sites. Furthermore, the use of a temperature-sensitive cI repressor allowed temperature-dependent transcription of the reporter gene.