The RPB2 flap loop of human RNA polymerase II is dispensable for transcription initiation and elongation.

Deletion of the flap loop in the Rp2 subunit of human RNAPII did not alter the ability of human RNAPII to initiate transcription or elongate the initiated transcripts in vivo and in vitro, and was also dispensable for elongation factor-mediated enhancement and inhibition of transcript elongation in vitro. ChIP:chip of wild-type and flap deletion human RNAPII revealed that the mutant RNAPII was not defective for promoter binding, initiation and elongation in vivo. Eight ChIP datasets were generated as log2(IP/input) fluorescence intensities using anti-FLAG IP of wild-type RPB2-FLAG cells in biological triplicate, anti-FLAG IP of delta-FL RPB2 FLAG cells in biological triplicate, and anti-RPB1 CTD, 8WG16 of both wild-type and delta-FL cells in biological duplicate. The two 8WG16- IP datasets were combined to measure the distribution of RPB1 signal.