BINDING OF CELLULAR REPRESSOR PROTEIN OR THE IE2 PROTEIN TO A CIS-ACTING NEGATIVE REGULATORY ELEMENT UPSTREAM OF A HUMAN CYTOMEGALOVIRUS EARLY PROMOTER
Lp. Huang et Mf. Stinski, BINDING OF CELLULAR REPRESSOR PROTEIN OR THE IE2 PROTEIN TO A CIS-ACTING NEGATIVE REGULATORY ELEMENT UPSTREAM OF A HUMAN CYTOMEGALOVIRUS EARLY PROMOTER, Journal of virology, 69(12), 1995, pp. 7612-7621
We have previously shown that the human cytomegalovirus early UL4 prom
oter has upstream negative and positive cis-acting regulatory,elements
. In the absence of the upstream negative regulatory region, the posit
ive element confers strong transcriptional activity. The positive elem
ent contains a CCAAT box dyad symmetry and hinds the cellular transcri
ption factor NF-Y. The effect of the negative regulatory element is ne
gated by the viral IE2 protein (L. Huang, C. L. Malone, and M. F. Stin
ski, J. Virol 68:2108, 1994). We investigated the binding of cellular
or viral IE2 protein to the negative regulatory region. The major cis-
acting negative regulatory element was located between -168 and -134 b
p relative to the transcription start site. This element could be tran
sferred to a heterologous promoter, and it functioned in either orient
ation. Mutational analysis demonstrated that a core DNA sequence in th
e cis-acting negative regulatory element, 5'-GTTTGGAATCGTT-3'; was req
uired for the binding of either a cellular repressor protein(s) or the
viral IE2 protein. The cellular DNA binding activity was present in b
oth nonpermissive HeLa and permissive human fibroblast cells but more
abundant in HeLa cells. Binding of the cellular repressor protein to t
he upstream cis-acting negative regulatory element correlates with rep
ression of transcription from the early UW promoter. Binding of the vi
ral IE2 protein correlates with negation of the repressive effect.