Activation of Bovine Immunodeficiency Virus(BIV) Gene Expression by Bovine Spumavirus(BSV)

Bovine spumavirus (BSV) 3026 China strain, which was isolated by authors, encodes the transcriptional transactivator Borf 1. The Borf 1 protein, as well as the BSV3026, can transactivate the gene expression directed by bovine immunodeficiency virus long terminal repeat (BIV LTR) in transient transfection assays. To identify the specific region in BIV LTR responsible for the Borf 1 action, it was examined that the effect of the Borf 1 on firefly luciferase (Luc) gene expression in transfected cells with a series of mutant pBIV LTR luc plasmids. The region between -410 and -115 from the transcription initiation site was identified as responsible for the transactivation by the Borf 1. However, the regions between -367 and -319 (NF B site), between -52 and +204, which are very important in the activation of BIV transcription, are dispensable for the Borf 1 mediated transactivation.