Yeast Rpb4, a subunit of RNA pol II is not essential for viability but is 
involved in multiple cellular phenotypes such as temperature sensitivity, 
enhanced pseudohyphal morphology, and decreased sporulation. Both in vivo and in 
vitro studies strongly support involvement of Rpb4 in transcription initiation, 
while its role in transcription elongation is not entirely consistent. Here we 
show that Rpb4 is not required for recruitment of RNA pol II on the coding 
region of YLR454w, a representative long gene. Yet we find strong genetic 
interaction of rpb4∆ with mutants in many transcription elongation factors such 
as Paf1, Spt4, Dst1, Elp3 and Rpb9. We demonstrate that, Rpb4 interacts 
functionally with Paf1 to affect the transcription elongation of the FKS1 gene. 
Our results suggest that while Rpb4 is not required for general transcription 
elongation, it could support transcription elongation for specific of class of 
genes by interaction with other elongation factors.