Abstract
Influenza A virus RNA genome exists as eight-segmented ribonucleoprotein complexes containing viral RNA polymerase and nucleoprotein (vRNPs). Packaging of vRNPs and virus budding take place at the apical plasma membrane (APM). However, little is known about the molecular mechanisms of apical transport of newly synthesized vRNP. Transfection of fluorescent-labeled antibody and subsequent live cell imaging revealed that punctate vRNP signals moved along microtubules rapidly but intermittently in both directions, suggestive of vesicle trafficking. Using a series of Rab family protein, we demonstrated that progeny vRNP localized to recycling endosome (RE) in an active/GTP-bound Rab11-dependent manner. The vRNP interacted with Rab11 through viral RNA polymerase. The localization of vRNP to RE and subsequent accumulation to the APM were impaired by overexpression of Rab binding domains (RBD) of Rab11 family interacting proteins (Rab11-FIPs). Similarly, no APM accumulation was observed by overexpression of class II Rab11-FIP mutants lacking RBD. These results suggest that the progeny vRNP makes use of Rab11-dependent RE machinery for APM trafficking.
Highlights
The viral genomes do not exist alone but form nucleoprotein complexes in which DNA/RNA genome is complexed with viral basic proteins, e.g., nucleocapsid protein for retrovirus [1] and core protein VII for adenovirus [2,3]
Live cell imaging of progeny virion ribonucleoprotein complexes (vRNPs) in the cytoplasm Our previous studies with paraformaldehyde-fixed cells found the potential of anti-NP mAb61A5 for detection of the vRNPs in the cytoplasm of influenza virus infected cells [44,45]
We showed that (i) progeny vRNP of influenza A virus was localized at recycling endosome (RE) and transported along microtubules; (ii) The localization required the interaction between active/GTPbound Rab11 and a heterotrimeric form of viral RNA-dependent RNA polymerase; and (iii) The Rab11-dependent interaction was required for the targeting of progeny vRNPs to the apical plasma membrane (APM), where virion packaging and budding take place
Summary
The viral genomes do not exist alone but form nucleoprotein complexes in which DNA/RNA genome is complexed with viral basic proteins, e.g., nucleocapsid protein for retrovirus [1] and core protein VII for adenovirus [2,3]. In the case of influenza A virus, a member of Orthomyxoviridae, a virion contains eight distinct segments of viral/virion ribonucleoprotein complexes (vRNPs) and each vRNP segment consists of a single-stranded negative-sense virion RNA (vRNA), viral RNA-dependent RNA polymerase (heterotrimer of PB2, PB1, and PA subunits), and nucleoprotein (NP) [4]. Both 59 and 39 termini of vRNA segment form a partially complementary double-stranded structure called ‘‘panhandle’’ [5,6] and function as promoter and replication origin for viral RNA synthesis. Both cRNA and progeny vRNA form viral RNP complexes, it has been shown that cRNP only localizes in the nucleus [11,12]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
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.
