RNA Polymerase II, DNA Directed Polypeptide I (POLR2I)

POLR2I encodes a subunit of RNA polymerase II, the polymerase responsible for synthesizing messenger RNA in eukaryotes. This subunit, in combination with two other polymerase subunits, forms the DNA binding domain of the polymerase, a groove in which the DNA template is transcribed into RNA. The product of this gene has two zinc finger motifs with conserved cysteines and the subunit does possess zinc binding activity.Yeast cells lacking RPB9 are unable to grow at high and low temperatures and are defective in mRNA start site selection. of POLR2I on a high copy number plasmid, but not on a low copy number plasmid, restored growth at high temperatures. Recombinant POLR2I was also able to correct the start site selection defect seen at the CYC1 promoter in vitro as effectively as the yeast RPB9 subunit.