TRANSCRIPTIONAL ANALYSIS AND PROMOTER ACTIVITY OF THE SPODOPTERA-LITTORALIS MULTICAPSID NUCLEOPOLYHEDROVIRUS ECDYSTEROID UDP-GLUCOSYLTRANSFERASE GENE

The ecdysteroid UDP-glucosyltransferase gene (egt) of Spodoptera litto ralis multicapsid nucleopolyhedrovirus (SpliMNPV) is a homologue of th e Autographa californica MNPV (AcMNPV) egt gene, which has been found to block insect moulting. Infection of larvae with an egt-deleted AcMN PV resulted in enhanced mortality as compared to infection with the wi ld-type virus. Consequently, deletion of an egt gene has been proposed as a tempting approach for enhancing the insecticidal properties of b aculoviruses. In a previous report we described the mapping and sequen cing of the SpliMNPV egt gene. Here we use time-course Northern blot a nd biochemical analyses to show the production of egt transcripts and protein. The SpliMNPV egt transcription start sites were mapped to 22 and 25 nucleotides downstream of the TATA box by primer extension. Tra nsient expression assays of chimeric egt promoter-chloramphenicol acet yltransferase (cat) reporter gene constructs revealed low promoter act ivity that was transactivated by AcMNPV immediate-early viral protein IE-1.