Atypical nucleoprotein complexes mediate CRE-dependent regulation of the early promoter of minute virus of mice

The P4 promoter of the parvovirus minute virus of mice (MVMp) directs trans cription of the genes encoding non-structural proteins. We have previously shown that functional upstream CRE elements contribute to both the ras onco gene-dependent activation of promoter P4 and its downmodulation by known ac tivators of cyclic AMP-dependent protein kinase A (PKA). In the present wor k, the nucleoprotein complexes formed with the P4 CRE elements were charact erized with regard to their polypeptide constituents and the nucleotides ta king part in the interaction. Atypical interactions, both at the protein-pr otein and protein-DNA level, were observed, which may be a reflection of th e divergence of the parvoviral CREs from the usual consensus. The CRE-media ted regulation of promoter P4 by PKA and pas is discussed in light of these findings.