Transient replication of BPV-1 requires two viral polypeptides encoded by the E1 and E2 open reading frames.

Abstract

Bovine papillomavirus (BPV) DNA is maintained as an episome with a constant copy number in transformed cells and is stably inherited. To study BPV replication we have developed a transient replication assay based on a highly efficient electroporation procedure. Using this assay we have determined that in the context of the viral genome two of the viral open reading frames, E1 and E2, are required for replication. Furthermore we show that when produced from expression vectors in the absence of other viral gene products, the full length E2 transactivator polypeptide and a 72 kd polypeptide encoded by the E1 open reading frame in its entirety, are both necessary and sufficient for replication BPV in C127 cells.

Characterization of the nuclear matrix targeting sequence (NMTS) of the BPV1 E8/E2 protein — the shortest known NMTS

“…52 The CHO derivatives CHO4.15 and CHOBgl40 are described in Piirsoo et al 53 As a well-transfected suspension cell line, we used the IcosageneCellFactory cell line CHOEB-NALT85 (described in patents EP1851319 and US 7790446 B2) derived from CHO-S cells (Invitrogen Corporation). This cell line expresses the EBV EBNA1 protein and the mouse polyomavirus large T antigen.…”

“…The pCGE2, pCGE2C and pCGE8/ E2 plasmids have been described previously in Ustav 1991. 52 Reporter plasmids for the transcription assay (3E2BS-Luc, URRLuc, pRL-TK) have been described previously. 25,54 The reporter plasmid 3E2BS-Luc contains 3 E2BS, 3 21-bp GC-rich repeats, and an enhancerless simian virus 40 early promoter in front of the firefly luciferase gene.…”

Development of human papillomavirus plasmids capable of episomal replication in human cell lines

“…Previous studies using three-plasmid systems, one expressing the HPV E1 protein, another the E2 protein and a plasmid containing the HPV ori have demonstrated HPV DNA replication in transfected fibroblast and epithelial cell lines. [10][11][12][13][14] In addition, in the case of HPV type 1a, the E1 protein alone was shown to be sufficient for replication of ori plasmids. 15 The E6 and E7 proteins of high-risk HPVs such as types 16 and 18 are involved in cellular transformation and target the cellular p53 and RB proteins, respectively.…”

“…16 However, it is important to note that the transforming E6 and E7 genes of HPVs are not required for HPV DNA replication, at least in short-term assays. [10][11][12][13][14] …”

“…16 However, it is important to note that the transforming E6 and E7 genes of HPVs are not required for HPV DNA replication, at least in short-term assays. [10][11][12][13][14] Also, the vegetative replication of HPV DNA is not necessary for their potential use as vectors for gene therapy since their DNA is maintained as a nuclear plasmid in latently infected cells. Bovine papillomavirus type 1 (BPV-1) vectors have been used to produce stable cell lines expressing foreign proteins.…”