Final answer:
ORF2 in LINES acts as a reverse transcriptase and also has endonuclease activity. The reverse transcriptase activity generates a complementary DNA copy of the transposable element, and the endonuclease activity degrades the RNA template after reverse transcription.
Step-by-step explanation:
ORF2 in LINES acts as a reverse transcriptase and also has endonuclease activity. The reverse transcriptase activity of ORF2 allows it to generate a complementary DNA (cDNA) copy of the transposable element.
This process involves the use of a tRNA molecule as a primer for the synthesis of the first strand of cDNA. The endonuclease activity of ORF2, specifically the RNAse H activity, degrades the RNA template after reverse transcription.