RNA Polymerase III, DNA Directed Polypeptide G (POLR3G)

Transcription by RNA polymerase III involves recruitment of the polymerase by template-bound accessory factors, followed by initiation, elongation, and termination steps. Human RNA Pol III is composed of 16 subunits, some of which are apparently modified in HeLa cells. Partial denaturing conditions and sucrose gradient sedimentation at high salt result in the dissociation of a subcomplex that includes hRPC32, hRPC39, and hRPC62. The human RNA Pol III core lacking the subcomplex functions in transcription elongation and termination following nonspecific initiation on a tailed template, but fails to show promoter-dependent transcription initiation in conjunction with accessory factors. hRPC32-hRPC39-hRPC62 subcomplex directs RNA Pol III binding to the TFIIIB-DNA complex via the interactions between TFIIIB and hRPC39.