Effects of repeated burst sequences on the p10 promoter activity of Bombyx mori nucleopolyhedrovirus

Abstract

• The use of repeated BSs inhibits the p10 promoter activity of Bombyx mori NPV. • The decrease in p10 promoter activity is a BS sequence specific result. • The p10 promoter has different transcription factors compared to the polyhedrin promoter. The burst sequence (BS) region within the promoter is very important for the burst expression of the very late promoters of baculovirus. As the use of repeated BSs in the polyhedrin promoter was reported to increase its activity, in this study, the effect of repeated BSs of the p10 promoter on the activity of the p10 promoter was investigated. The effect of repeated BSs was determined through analysis of virus-induced transient expression and the generation of recombinant viruses. It was observed that the use of repeated BSs downstream of the p10 promoter strongly inhibited the activity of the p10 promoter. However, the insertion of noncoding sequences instead of repeated BSs into the p10 promoter led to a very weak decrease in the activity of the p10 promoter, rather than the strong decrease caused by repeated BSs. These results indicated that the decrease in p10 promoter activity was BS-specific. In addition, it was suggested that although the polyhedrin promoter and the p10 promoter share a number of transcription factors, there are also transcription factors that bind only one of these promoters and not the other.