Abstract
Gag proteins play an important role in many stages of the retroviral replication cycle. They orchestrate viral assembly, interact with numerous host cell proteins, engage in regulation of viral gene expression, and provide the main driving force for virus intracellular trafficking and budding. Foamy Viruses (FV), also known as spumaviruses, display a number of unique features among retroviruses. Many of these features can be attributed to their Gag proteins. FV Gag proteins lack characteristic orthoretroviral domains like membrane-binding domains (M domains), the major homology region (MHR), and the hallmark Cys-His motifs. In contrast, they contain several distinct domains such as the essential Gag-Env interaction domain and the glycine and arginine rich boxes (GR boxes). Furthermore, FV Gag only undergoes limited maturation and follows an unusual pathway for nuclear translocation. This review summarizes the known FV Gag domains and motifs and their functions. In particular, it provides an overview of the unique structural and functional properties that distinguish FV Gag proteins from orthoretroviral Gag proteins.
Highlights
While the retroviral envelope protein (Env) mediates the important steps of receptor binding and membrane fusion, andPol provides the key enzymatic functions required for viral replication, it is the Gag protein that is the major structural component of the viral particle
Whereas the subfamily of orthoretroviruses consists of six genera, the subfamily of spumaretroviruses consist of only one genus—the spumaviruses, termed Foamy Viruses (FV)
If amino acid positions are specified in the text these refer to the respective position in prototype FV (PFV) Gag, statements are generalized if applicable
Summary
While the retroviral Env mediates the important steps of receptor binding and membrane fusion, and. Pol provides the key enzymatic functions required for viral replication, it is the Gag protein that is the major structural component of the viral particle. The viral genome, and accessory proteins; (v) is involved in spatiotemporal regulation of the essential, viral, enzymatic reactions; and (vi) is essential for viral budding [reviewed in 1]. FVs share the major characteristics of retroviruses in that they reverse-transcribe and integrate their genome, FV replication deviates in many aspects from that of orthoretroviruses [reviewed in 4,5]. In particular the FV Gag proteins have strikingly different domains and functions compared to orthoretroviral Gag, many of which are reminiscent of another reverse transcriptase encoding virus family—the hepadnaviruses [reviewed in 6]. This review summarizes the current knowledge of the different FV Gag domains and motifs and their functions, highlighting common features, but more importantly concentrating on the differences between foamyviral and orthoretroviral Gag proteins. If amino acid positions are specified in the text these refer to the respective position in PFV Gag, statements are generalized if applicable
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
