Identification
of Functional Region of Helicase Gene Promoter in
Nuclear Polyhedrosis Virus
XIAO Qing-Li, ZHANG Zhi-Fang*, YI
Yong-Zhu, HE Jia-Lu, WU Xiang-Fu1
( Key Laboratory of Silkworm Biotechnology, Ministry of Agriculture,
Sericultural Research Institute, Chinese
Academy of Agricultural Sciences,
Zhenjiang 212018, China;1Institute of Biochemistry and Cell Biology,
Shanghai
Institutes for Biological Sciences, the
Chinese Academy of Sciences, Shanghai 200031, China )
Abstract DNA
helicases are essential for replication of baculoviruses. It was found that the
helicase gene promoter of
virus, including 510 bp upstream of ATG, had both early and late RNA initiation
sites and could be recognized by cellular RNA polymerase. Transient expression
assays in uninfected Sf-21 cells indicated that the helicase gene promoter could
be classified as a delayed-early gene promoter. Deletion analysis by PCR showed
that the regulation region of its basic transcription was mainly within -510 to
-410 bp upstream of ATG. However, the basic activity was still detected with a
deletion to -98 bp relative to ATG. In the presence of viral factors, deletion
between -510 to -410 bp relative to ATG did not significantly reduce the
promoter activity compared to the full-length promoter (510 bp). The remarkable
reduction in the promoter activity was observed with continuous deletions. It
suggests, therefore, that
viral factors are mainly located within the range of -410 to -309 bp upstream
of ATG.
Key words Bombyx mori nuclear polyhedrosis
virus; helicase gene promoter; transient expression; deletion analysis
*Corresponding authors: Tel,
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