Abstract
A type IV secretion system (T4SS) is used by many symbiotic and pathogenic intracellular bacteria for the successful infection of and survival, proliferation, and persistence within hosts. In this study, the presence and function of the T4SS in Wolbachia strains were investigated by a combination of genetic screening and immunofluorescence microscopy. Two operons of virB-virD4 loci were found in the genome of Wolbachia pipientis strain wAtab3, from the Hymenoptera Asobara tabida, and strain wRi, infecting Drosophila simulans. One operon consisted of five vir genes (virB8, virB9, virB10, virB11, and virD4) and the downstream wspB locus. The other operon was composed of three genes (virB3, virB4, and virB6) and included four additional open reading frames (orf1 to orf4) orientated in the same direction. In cell culture and insect hosts infected with different Wolbachia strains, the bona fide vir genes were polycistronically transcribed, together with the downstream adjacent loci, notably, as virB8 to virD4 and wspB and as virB3, virB4, virB6, and orf1 to orf4. Two peptides encompassing conserved C and N termini of the Wolbachia VirB6 protein were used for the production of polyclonal antibodies. Anti-VirB6 antibodies could detect the corresponding recombinant protein by chemifluorescence on Western blots of total proteins from Escherichia coli transformants and Wolbachia strains cultured in cell lines. Using immunofluorescence microscopy, we further demonstrated that the VirB6 protein was produced by Wolbachia strains in ovaries of insects harboring wAtab3 or wRi and cell lines infected with wAlbB or wMelPop. As VirB6 is known to associate with other VirB proteins to form a membrane-spanning structure, this finding suggests that a T4SS may function in Wolbachia.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: 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.