Unidirectional deletion and linker scan analysis of the late promoter of the human papovavirus BK.

We have previously shown that the late promoter of the human papovavirus BK (prototype) is contained within the three 68-bp repeats and a 66-bp region to the late side of the repeats which together constitute the early promoter enhancer. We have now carried out unidirectional deletion and linker scan analyses of these sequences to identify the major elements of the late promoter in human and monkey cells. Several important sequence motifs involved in late promoter function are found throughout this region. The most active ones correspond to previously defined binding sites for the transcription factors NF1 and Sp1 and a GC-rich region known to be important for early promoter function. The NF1 sequences may also be involved in negative regulation in some situations.