Synthesis of RNA transcripts by RNA polymerase II (Pol II) is the first step towards protein synthesis and a major point of regulation of gene expression.
Mediator, a multi subunit protein acts as a coregulatory complex for RNA Pol II. A role for Mediator has also emerged in the regulation of transcript elongation as it helps in recruiting the elongation factors to the genes and controlling the phosphorylation state of the C-terminal domain of the largest Pol II subunit. In metazoa, the MED26 subunit of Mediator acts as a docking site for elongation factors and super elongation complexes (SEC). ELL/EAF family members, positive transcription elongation factor b (P-TEFb) and other coregulators like AFF4, AFF1, ENL and AF9 form part of the SEC complex.
ELL and EAF have been implicated in control of promoter proximal pausing and transcription elongation. ELL and EAF orthologs were not identified in fungi until recently. Previous data from our lab identified genes in S. pombe (Sp) similar to ELL and EAF, which are not present in S. cerevisiae. SpELL and SpEAF also interact with each other to form a heterodimer and can positively regulate transcription by RNA pol II.We are interested to understand ELL1/EAF1 (SpELL/SpEAF) function in S. pombe and to determine whether SpELL and SpEAF function with additional proteins. We also are trying to define the Mediator complex of S. pombe and to explore the connection between the Mediator complex and SpELL and SpEAF.