Direct transactivator-transcription factor IID (TFIID) contacts drive yeast ribosomal protein gene transcription.
Transcription factor IID (TFIID) plays a key role in regulating eukaryotic gene expression by directly binding promoters and enhancer-bound transactivator proteins. However, the precise mechanisms and outcomes of transactivator-TFIID interaction remain unclear. Transcription of yeast ribosomal protein genes requires TFIID and the DNA-binding transactivator Rap1. We have previously shown that Rap1 directly binds to the TFIID complex through interaction with its TATA-binding protein-associated factor (Taf) subunits Taf4, -5, and -12. Here, we identify and characterize the Rap1 binding domains (RBDs) of Taf4 and Taf5. These RBDs are essential for viability but dispensable for Taf-Taf interactions and TFIID stability. Cells expressing altered Rap1 binding domains exhibit conditional growth, synthetic phenotypes when expressed in combination or with altered Rap1, and are selectively defective in ribosomal protein gene transcription. Taf4 and Taf5 proteins with altered RBDs bind Rap1 with reduced affinity. We propose that collectively the Taf4, Taf5, and Taf12 subunits of TFIID represent the physical and functional targets for Rap1 interaction and, furthermore, that these interactions drive ribosomal protein gene transcription.
Layer
Justin H
JH
Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0615.
Miller
Scott G
SG
Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0615.
Weil
P Anthony
PA
Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0615. Electronic address: tony.weil@vanderbilt.edu.
D001665:Binding Sites; D005656:Fungal Proteins / Q000235:genetics*; D016133:Polymerase Chain Reaction; D011485:Protein Binding; D012269:Ribosomal Proteins / Q000235:genetics*; D015534:Trans-Activators / Q000378:metabolism*; D035362:Transcription Factor TFIID / Q000378:metabolism*; D014158:Transcription, Genetic
D005656:Fungal Proteins; D012269:Ribosomal Proteins; D015534:Trans-Activators; D035362:Transcription Factor TFIID