Transcription of the baculovirus polyhedrin gene reduces the levels of an antisense transcript initiated downstream.

A late 3.2-kilobase (kb) RNA initiated approximately 2 kb downstream of the 3' end of the Autographa californica nuclear polyhedrosis virus polyhedrin-coding sequence and traversed the polyhedrin gene in an antisense direction. This RNA was sense RNA for the two open reading frames flanking the polyhedrin gene. A mutant virus, vXpoly, which differs from wild-type virus only at the essential RNA initiation site in the polyhedrin promoter, exhibited higher levels of the 3.2-kb RNA than did wild-type virus during the polyhedrin transcriptional phase. Thus, transcription of the polyhedrin gene down regulates the levels of this 3.2-kb RNA.