The Chilo iridescent virus DNA polymerase promoter contains an essential AAAAT motif (original) (raw)
Abstract
The delayed-early DNA polymerase promoter of Chilo iridescent virus (CIV), officially known as Invertebrate iridescent virus, was fine mapped by constructing a series of increasing deletions and by introducing point mutations. The effects of these mutations were examined in a luciferase reporter gene system using Bombyx mori cells transfected with promoter constructs and infected with CIV. When the size of the upstream element was reduced from position −19 to −15, relative to the transcriptional start site, the luciferase activity was reduced to almost zero. Point mutations showed that each of the 5 nt (AAAAT) located between –19 and –15 were equally essential for promoter activity. Mutations at individual bases around the transcription initiation site showed that the promoter extended until position −2 upstream of the transcription start site. South-Western analysis showed that a protein of approximately 100 kDa interacted with the −19 nt promoter fragment in CIV-infected cells. This binding did not occur with a point mutant that lacked promoter activity. The AAAAT motif was also found in the DNA polymerase promoter region of other iridoviruses and in other putative CIV delayed-early genes.
- Received: 23/02/2007
- Accepted:09/05/2007
- Published Online:01/09/2007
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/content/journal/jgv/10.1099/vir.0.82947-0
2007-09-01
2025-01-18
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