Final answer:
The integration of a provirus or transposon into host DNA is mediated by enzymes such as integrase and transposase. These enzymes prepare the DNA ends for ligation, and following the integration, DNA replication and ligation steps finalize the insertion of the genetic element into the host genome.
Step-by-step explanation:
The process described in the question involves integrase, an enzyme that is crucial in the integration of a provirus into the host DNA. Proviral integration includes the following steps: first, the transposase or reverse transcriptase enzyme makes a nick in the DNA and processes the 3' ends, creating a staggered cut to excise the transposon or reverse-transcribe the retroelement.
Following this, integrase or transposase brings the transposon ends together, attacking the DNA at a new insertion site, creating staggered ends. Next, the enzyme ligates the 3'OH ends of the transposon or retrotransposon cDNA to the 5'OH ends of the target DNA. Finally, DNA replication takes place to fill in the missing bases, regenerating direct repeats of host cell genomic DNA at the insertion site. A final ligation step by DNA ligase seals the transposon in its new genomic location, completing the integration process.