Disease relevance of pol

• The roles of Pol and Env in the assembly pathway of human foamy virus [1].
• The Pol protein is not required for capsid assembly, and the Env surface glycoprotein is not required for release of virions from the cell [1].
• Furthermore, replacement of the Met residue by Thr at position 9 in pol within the gag-pol overlap region resulted in strongly reduced HFV Pol polyprotein expression and infectivity of the resulting proviruses [2].
• Three different adenoviruses are used to encode: (i) the PFV structural genes gag and pol (Ad-GagPolDeltaPacI); (ii) the PFV structural gene env (Ad-Env); and (iii) the PFV vector genome (Ad-MD9) encoding the transgene (the enhanced green fluorescent protein (eGFP) gene) [3].
• This genome organization suggests either a + 1 ribosomal frameshift to generate a Gag-Pol fusion protein, similar to all other retroviruses studied so far, or new initiation of Pol translation, as used by pararetroviruses, to express the Pol protein [4].

High impact information on pol

• In contrast, the Pol protein of HFV is translated from a spliced messenger RNA and lacks Gag domains [5].
• One PES is located in the U5 region of the 5' long terminal repeat and one at the 3' end of the pol gene region [6].
• To gain more information on how the 120-kDa Pro-Pol protein is synthesized, mutant HFV genomes were constructed and the resulting proviruses were analyzed with respect to HFV pol expression and infectivity [2].
• Our data show that the carboxy-terminal p3Gag protein has an important function for viral infectivity but is not required for preassembly of capsids, virus morphogenesis, and incorporation of Pol proteins into virions [7].
• This virus was unable to express detectable Pol proteins after transient transfection [8].

Biological context of pol

• Using a transient FV vector transfection system, it is shown that pregenomic RNA is required for efficient virion incorporation of functionally active Pol and that protein-protein interactions of Pol with Gag are not sufficient to complete particle assembly [9].
• Simian foamy virus type 3 (SFV-3) is a retrovirus that has a complex genome organization and encodes two open reading frames (ORF-1 and ORF-2) in addition to the genes coding for gag, pol, and env [10].
• Indicator gene assays suggest that this other mechanism is likely to be a transactivator-dependent cryptic promoter in the gag gene which gives rise to Pol-encoding transcripts [8].

Associations of pol with chemical compounds

• Oligopeptides that correspond to proteolytic cleavage site junctions of the native Gag and Pol proteins are specifically cleaved by retroviral aspartate proteases (PRs) [11].

Analytical, diagnostic and therapeutic context of pol

• To delineate the proteolytic cleavage sites between the Pol subdomains, recombinant human foamy virus (HFV) Pol proteins were expressed, purified by affinity chromatography, and subjected to either HFV protease assays or autocatalytic processing [12].

References