INTRAMOLECULAR RECOMBINATION IN POLYOMAVIRUS DNA IS CONTROLLED BY PROMOTER ELEMENTS

We show here that intramolecular homologous recombination in polyomavi rus (Py) DNA depends upon discrete sequence elements of the viral regu latory region which are believed to regulate transcription initiation and exert little or no cis-control over replication. Either deleting t he viral early promoter (EP) or inverting the viral late promoter (LP) strongly impairs viral DNA recombination under conditions allowing vi ral DNA replication to proceed undisturbed. These findings suggest tha t bi-directional transcription proceeding from the intergenic region f avors intramolecular recombination.