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Why can DNA made by reverse transcriptase become part of a host cell’s genome?

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Diagram illustrating the process of retrovirus infection and reverse transcription, showing a retrovirus entering a host cell, releasing viral RNA, reverse transcriptase converting RNA to DNA, integration into the host genome, transcription of new viral RNA, assembly of new virions, and budding from the cell. — Reverse transcriptase After a retrovirus infects a cell, an enzyme known as reverse transcriptase converts viral RNA into proviral DNA in the cytoplasm. Proviral DNA then enters the nucleus, where it is incorporated into the host cell's DNA.

DNA synthesized by reverse transcriptase can become part of a host cell’s genome because the enzyme facilitates the conversion of a retrovirus’s RNA genome into double-stranded DNA, known as proviral DNA.12

Once this DNA is synthesized, it is integrated into the host cell's chromosomal DNA through the action of another enzyme called integrase. This integration process is guided by specific nucleotide sequences at the ends of the viral genome, known as long terminal repeats (LTR), which allow the proviral DNA to recognize and insert itself into the host cell's genetic material.2

Once integrated, the viral DNA is treated as part of the host's own genome. It replicates alongside the host cell's chromosomes during cell division, ensuring that each daughter cell receives a copy of the viral genetic information. This mechanism is fundamental to the life cycle of retroviruses, such as HIV, and can lead to persistent infection or malignant transformation of the host cell.321