Yeast TAF(II)90 is required for cell-cycle progression through G₂/M but not for general transcription activation

The RNA polymerase II general transcription factor TFIID is a multisubunit complex comprising TATA-box binding protein and associated factors (TAF(II)s). In vitro experiments have suggested that TAF(II)s are essential coactivators required for RNA polymerase II-directed transcription activation. Here, for the first time, we analyze systematically the in vivo function of a specific TAF(II), yeast TAF(II)90 (yTAF(II)90). We show that functional inactivation of yTAF(II)90 by temperature-sensitive mutations or depletion leads to arrest at the G₂/M phase of the cell cycle. Unexpectedly, in the absence of functional yTAF(II)90, a variety of endogenous yeast genes were all transcribed normally, including those driven by well-characterized activators. Taken together, our results indicate that yTAF(II)90 is not required for transcription activation in general, and reveal linkages between TAF(II) function and cell-cycle progression.