Sub1, two domains, two functions: transcription initiation versus elongation

Abstract

We have performed a detailed analysis of the ssDNA binding and C-terminal domains of Sub1 from S. cerevisiae and identified the essential residues involved in Sub1 DNA binding capacity, which are not required during transcription elongation. Additionally, our data indicates that the C-terminus domain of Sub1, the function of which was previously unknown, might be important in promoting Sub1 release from the promoter to facilitate transcription elongation. In summary, Sub1 plays a dual function during transcription, being a pre-initiation factor via its DNA binding domain, and a transcription elongation factor through its C-terminus domain.