Final answer:
The correct answer is option 4. The false statement is that the 5-recessed ends of LTRs are linked to staggered 3 ends of the target DNA during retrovirus integration; it is actually the 3'-recessed ends that are linked to the staggered 5' ends of the target DNA.
Step-by-step explanation:
The false statement among the provided options is: During integration of the retrovirus linear DNA into the host genome to form the provirus, the 5-recessed ends of LTRs are linked to staggered 3 ends of the target DNA.
During retroviral integration, it is the 3'-recessed ends of the linear DNA of the retrovirus that are joined to the staggered 5' ends of the host DNA. Integrase catalyzes the strand transfer reaction where it cuts the genomic DNA and joins the 3' ends of the viral DNA to it. The 5' ends of the viral DNA are left unjoined, creating two single-strand gaps at the junction that are filled in by cellular repair mechanisms.
This step completes the integration and results in the duplication of a few nucleotides of the host DNA at the integration site, which become the long terminal repeats (LTRs). Typically, during this process of integration, integrase cleaves two nucleotides from the 3' ends of the viral DNA, so the corrected statement would be that two bases from each of the 3' protruding ends of retrovirus LTRs are deleted during the integration into the provirus.