Replicase

Alphavirus replicase genes are expressed in addition to the vaccine insert.

For RNA-based phages, RNA replicase is synthesized early in the process.

One of these includes RNA-dependent RNA polymerase (RNA replicase), which copies the viral RNA to form a double-stranded replicative form.

The gene encoding the antigen of interest is inserted into the alphavirus replicon, replacing structural genes but leaving non-structural replicase genes intact.

This means that the virus must bring along with it the RNA replicase enzyme.

This replication machineries are called replisomes or DNA replicase systems, these terms mean originally a generic term for proteins located on replication forks.