Both proviral and episomal latency may require maintenance for continued infection and fidelity of viral genes. Latency is generally maintained by viral genes expressed primarily during latency. Expression of these "latency-associated" genes may function to keep the viral genome from being digested by cellular ribozymes or being found out by the immune system. Certain viral gene products (RNA transcripts such as non-coding RNAs and proteins) may also inhibit apoptosis or induce cell growth and division to allow more copies of the infected cell to be produced.