MAPPING OF UPSTREAM REGULATORY ELEMENTS IN THE P4 PROMOTER OF PARVOVIRUS MINUTE VIRUS OF MICE

The early promoter (P4) of the autonomous parvovirus minute virus of m ice (prototype strain) directs the expression of the transcription uni t coding for the nonstructural proteins NS1 and NS2. Although proximal promoter elements (GC and TATA boxes) are essential for P4 activity i n vivo, additional upstream sequences appear to be required for optima l transcription. Therefore, associations of proteins with the upstream regulatory region of promoter P4 were studied in the rat fibroblast c ell line FRE14 by gel retardation and in vitro as well as in vivo foot printing assays. This led to the identification of at least four disti nct upstream elements that interacted with cellular proteins. The func tionality of these elements was supported by the reduced level of gene expression driven by corresponding linker-substitutive mutants of pro moter P4. (C) 1994 Academic Press, Inc.