The role of activators in assembly of RNA polymerase II transcription complexes.

The past year has provided new insights into the biochemical mechanism of gene activation. Key discoveries include the finding that TFIIA plays an important regulatory role in transcription complex assembly, the TBP-associated factors are direct targets of at least two classes of activator, and a largely pre-assembled transcription complex has been isolated from yeast cells, challenging the step-wise assembly pathway. This review also presents an update on the argument that TFIIB is the target of VP16 and insights into the energetic role of ATP in RNA polymerase II initiation.