In molecular genetics, long terminal repeats (LTRs) are found in retroviral DNA flanking functional genes (example: LTR-PBS-PSI-GAG-POL-ENV-LTR). The LTRs are partially transcribed into an RNA intermediate, followed by reverse transcription into complementary DNA (cDNA) and ultimately dsDNA (double-stranded DNA) with full LTRs. The LTRs then mediate integration of the retroviral DNA via an LTR specific transposase called integrase into another region of the chromosome. This is the basic mechanism used by the Human Immunodeficiency Virus (HIV).
