Polymerase protein (Pol protein) (Pol)

Polymerase protein (Pol protein) is the multifunctional enzyme encoded by the pol gene of retroviruses (such as HIV-1) and hepadnaviruses (such as hepatitis B virus)[4][6][7]. In HIV-1, Pol is expressed as part of the Gag–Pol fusion polyprotein and subsequently processed by viral protease into three catalytic domains: protease (PR), reverse transcriptase (RT), and integrase (IN)[7][15]. These enzymes are central to the viral lifecycle: the protease is needed for polyprotein processing and maturation, reverse transcriptase transcribes the viral RNA genome into DNA, and integrase facilitates genomic integration into the host cell DNA[9][13]. In hepatitis B virus, Pol is also a multifunctional enzyme with reverse transcriptase and RNase H activities, critical for viral replication[6]. The Pol protein is a well-established therapeutic target; drugs inhibiting its enzymatic activities (RT, IN, PR) form the cornerstone of current HIV and HBV antiviral regimens. Resistance mutations in Pol are used as biomarkers for drug resistance profiling in treated patients. Therapeutic challenges include the emergence of drug resistance mutations, off-target toxicity (notably inhibition of human DNA polymerases by nucleoside analogues), and management of side effects such as hepatotoxicity[13][15]. The term "Pol antigen" originates from its recognition by host immune responses and utilization in diagnostic assays, but in contemporary usage it generally refers to the viral polymerase itself.

Other names

Pol proteinPolymerase antigenViral polymeraseHBV Pol (in context of Hepatitis B)HIV-1 Pol (in context of HIV)Reverse transcriptase (for the RT domain)Viral protease (for the PR domain)Integrase (for the IN domain)

Inhibition of reverse transcriptase (antiretroviral nucleoside and non-nucleoside inhibitors); Inhibition of viral integrase (integrase inhibitors); Inhibition of viral protease (protease inhibitors)