high mobility group (HMG)-box found in Saccharomyces cerevisiae repressor ROX1 and similar proteins
This family includes class I members of the HMG-box superfamily of DNA-binding proteins, including Saccharomyces cerevisiae repressor ROX1, Schizosaccharomyces pombe mating-type M-specific polypeptide Mc (mat-Mc), Schizosaccharomyces pombe transcription factor ste11, Podospora anserina MAT+ sexual cell fertilization-promoting factor (FPR1), Podospora anserina sporulation minus regulator 2 (SMR2) and Candida albicans repressor of filamentous growth 1 (RFG1). These proteins contain a single HMG box, and bind the minor groove of DNA in a highly sequence-specific manner. ROX1, also called heme-dependent repression factor, or hypoxic function repressor, is a transcription factor that represses the expression of HEM13, COX5B, ANB1, CYC7 or AAC3. It binds to the DNA sequence 5'-RRRTAACAAGAG-3'. mat-Mc belongs to the mating type protein family, which contains sequence specific DNA-binding proteins that act as master switches in yeast differentiation by controlling gene expression in a cell type-specific fashion. mat-Mc is a positive regulator of MFM genes and is required for conjugation and efficient meiosis. Its HMG box recognizes the DNA sequence 5'-AACAAAG-3'. Ste11 is a key transcription factor for sexual development. It activates the transcription of the matp, matm, mei2, mfm, ste6 and rgs1 genes. It binds specifically to a DNA fragment carrying a 10-base motif 5'-TTCTTTGTTY-3'. FPR1 controls fertilization, probably by determining the mating type. SMR2 is a transcription factor that is required for post-fertilization events. It is required for the developmental events that occur in the female organ after fertilization. RFG1 is a transcription regulator that functions in both the positive and negative regulation of filamentous growth, depending upon environmental conditions.