Effect Of Rab6a On The Replication Of Classical Swine Fever Virus In PK-15 Cells

Classical swine fever,caused by Classical swine fever virus,is a highly contagious,often fatal porcine disease that causes significant economic losses.Like other eukaryotic viruses,CSFV must complete its own replication and proliferation by means of the components of the host cell.Rab6 a is a small GTPase that localizes to the Golgi of the host cell and is an important regulator of vesicle transport.The aim of this study was to investigate the effect of Rab6 a protein on CSFV replication and to understand the changes in the distribution of CSFV E2 protein in cells.This study provides new scientific information for elucidating the regulation of Rab6 a protein on CSFV replication.The following research results were obtained.(1)Rab6a has a positive regulatory effect on CSFV replication.After knocking down Rab6 a expression,CSFV replication was significantly inhibited(P<0.05);after overexpression of Rab6 a,CSFV replication was significantly promoted(P<0.05).Mutant Rab6 a Q72L(GTP)and Rab6 a T27N(GDP)significantly inhibited CSFV replication(P<0.05),it is suggested that the normal conversion of the GTP form and the GDP form of the Rab6 a protein is an important factor in CSFV replication.(2)Rab6a promotes the production of CSFV infectious virions.After the expression of Rab6 a was disturbed,the yield of infectious virions in the supernatant of the cells was significantly decreased;After overexpression of Rab6 a,the yield of infectious virions in the supernatant of the cells was significantly promoted;The yield of infectious virions in the supernatants of the mutants treated with Rab6 a Q72L(GTP)and Rab6 a T27N(GDP)were significantly decreased,indicating that Rab6 a has promotes the production of CSFV infectious virions.(3)Rab6a mediates intracellular transport of E2 protein.PK-15 cells were co-transfected with Rab6 a and E2 protein recombinant plasmids.The distribution of E2 protein in the cells was observed by laser confocal microscopy.It was found that Rab6 a mediates the transport of CSFV E2 protein from the periphery of the nucleus to the cell membrane.(4)There was no significant effect on the transcriptional level and protein level of intracellular Rab6 a in PK-15 cells infected with classical swine fever virus.The effect of CSFV infection with PK-15 cells on the transcription level and protein expression of Rab6 awas detected by real-time PCR and Western blot,the results showed that the transcription level and protein expression of Rab6 a did not change significantly after CSFV infected PK-15 cells(P>0.05).In summary,this study found that Rab6 a protein promotes the replication of CSFV and plays an important role in the production of CSFV progeny virus;Rab6a protein mediates the transport of CSFV E2 from the periphery of the nucleus to the cell membrane.The results provide new scientific information to further elucidate the effect of the Rab family on CSFV replication and to understand the transport of CSFV in host cells.