Telomerase RNA bound by protein motifs specific to telomerase reverse transcriptase

Telomerase reverse transcriptase (TERT) differs from many other reverse tra nscriptases in that it remains stably associated with its template-containi ng RNA subunit. Elements of TERT involved in binding the RNA subunit have n ow been identified by mutagenesis and in vitro reconstitution of the Tetrah ymena ribonucleoprotein complex. Mutations in the reverse transcriptase mot ifs of TERT reduced activity as expected but did not greatly reduce its bin ding to the telomerase RNA. In contrast, all mutations in the T and CP moti fs dramatically reduced RNA binding. We therefore suggest that the T and CP motifs of TERT function to hold on to the telomerase RNA, leaving the RNA template region free to translocate through the RT domain.