Abstract
Bovine leukaemia virus (BLV) induces syncytia in productively infected ovine and bovine monolayer cells. Expression of the env gene directly determines the syncytium-forming activity, since the expression of a cloned env gene directed by the simian virus 40 (SV40) early promoter efficiently induced syncytia in transfected ovine embryonic (OE) cells. However a BLV long terminal repeat (LTR)-directed expression plasmid (pLTRenv) failed to induce syncytia in transfected OE cells, suggesting insufficient promoter activity of the LTR sequences. To assess the role of the XBL genes, which are located in the 3' distal region of the genome, in viral gene expression we constructed SV40 early promoter-directed expression plasmids. These contained open reading frames (ORFs) in the XBL region, and were examined for syncytium-inducing activity by cotransfection with pLTRenv. The results suggest that both XBL-I (the longest ORF: x-lor) and XBL-II (a shorter overlapping ORF: x-sor) are trans-acting genes which cooperatively activate LTR-directed viral gene expression.
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.
