What is type IV viral replication?
Type IV viral replication always refers to a retrovirus. These viruses have a genome with a single stranded positive polarity RNA. Usually positive polarity RNA can immediately serve as mRNA, but in retroviruses it is injected into the cytoplasm along with reverse transcriptase which immediately acts to synthesize a negative polarity strand of DNA. Next a positive polarity DNA strand is synthesized and incorporated into the hosts DNA enzyme integrase. From there the DNA can be transcribed into mRNA and proteins can be made to construct new virions.