The Epstein-Barr virus BMLF1 promoter contains an enhancer element that is responsive to the BZLF1 and BRLF1 transactivators.
We have previously shown that the Epstein-Barr virus (EBV) immediate-early gene product, BZLF1, can activate expression of the EBV BMLF1 immediate-early promoter in EBV-positive, but not EBV-negative, B cells, suggesting that the BZLF1 effect may be mediated through another EBV gene product (S. Kenney, J. Kamine, E. Holley-Guthrie, J.-C. Lin, E.-C. Mar, and J. S. Pagano, J. Virol. 63:1729-1736, 1989). Here, we show that the EBV BRLF1 immediate-early gene product transactivates the BMLF1 promoter in either EBV-positive or EBV-negative B cells. Deletional analysis revealed that both the BZLF1-responsive region and the BRLF1-responsive region of the BMLF1 promoter are contained within the same 140-base-pair FokI-PvuII fragment located 300 base pairs upstream of the mRNA start site. This FokI-PvuII fragment functions as an enhancer element in the presence of the BRLF1 transactivator and contains the sequence CCGTGGAGA ATGTC, which is strikingly similar to the BRLF1-responsive region of the EBV DR/DL enhancer (A. Chevallier-Greco, H. Gruffat, E. Manet, A. Calender, and A. Sergeant, J. Virol. 63:615-623, 1989). The effect of BZLF1 on the BMLF1 promoter is likely to be indirect and mediated through the BRLF1 transactivator.
Kenney
S
S
Department of Medicine, University of North Carolina, Chapel Hill 27514.
Holley-Guthrie
E
E
Mar
E C
EC
Smith
M
M
D001483:Base Sequence; D015500:Chloramphenicol O-Acetyltransferase / Q000235:genetics; D004742:Enhancer Elements, Genetic; D015696:Gene Products, tat; D004854:Herpesvirus 4, Human / Q000235:genetics*; D009154:Mutation; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000032:analysis; D014157:Transcription Factors / Q000502:physiology*; D014764:Viral Proteins / Q000502:physiology*
D015696:Gene Products, tat; D012333:RNA, Messenger; D014157:Transcription Factors; D014764:Viral Proteins; D015500:Chloramphenicol O-Acetyltransferase