Multiple domains of Mata1 transcription factor contribute to binding site specificity

Abstract

Among homologous transcription factors with the same function, DNA-binding specificity can diverge. Mat1 is a high mobility group (HMG) box transcription factor in budding yeast whose Saccharomyces cerevisiae and Candida albicans homologs regulate -specific genes but bind distinct cis-regulatory sequences. To identify the protein features underlying this divergence, we generated structure-guided chimeras and measured their activity using species-specific reporters. Replacing any of the four Mat1 regions reduced activation of the S. cerevisiae reporter, while all chimeras retained activity on the C. albicans reporter. Thus, all four regions of Mat - not just the HMG box domain - are important for sequence specificity.