Not to be confused with DNA-dependent RNA polymerase. RNA-dependent RNA polymerase (RdRp), (RDR), or RNA replicase, is an enzyme that catalyzes the replication of RNA from an RNA template. This is in contrast to a typical DNA-dependent RNA polymerase, which catalyzes the transcription of RNA from a DNA template.RNA-dependent RNA polymerase (RdRp) is an essential protein encoded in the genomes of all RNA-containing viruses with no DNA stage that have sense negative RNA.It catalyses synthesis of the RNA strand complementary to a given RNA template.The RNA replication process is a two-step mechanism.ot to be confused with DNA-dependent RNA polymerase. RNA-dependent RNA polymerase (RdRp), (RDR), or RNA replicase, is an enzyme that catalyzes the replication of RNA from an RNA template. This is in contrast to a typical DNA-dependent RNA polymerase, which catalyzes the transcription of RNA from a DNA template.