We are interested in the control of transcription in eukaryotes, particularly the great switch in transcription that occurs when viruses infect their host cells. We are studying a baculovirus -- a DNA virus that infects caterpillars. Transcription in insect cells infected by this virus occurs in three stages: early, late, and very late. The switch from early to late transcription occurs at the onset of viral DNA replication 6-7 hours post-infection.
The switch from late to very late transcription occurs at about 18 hours post- infection, which is coincident with the beginning of production of polyhedral inclusion bodies that contain virus particles that spread the infection from animal to animal. Early transcription in baculovirus-infected cells is catalyzed by the host RNA polymerase II. Late and very late transcription is catalyzed by a novel viral RNA polymerase discovered in our laboratory. Very late transcription occurs primarily in two genes: polyhedrin and p10. This transcription is extremely active, and is commonly used to drive expression of foreign genes in recombinant baculoviruses, under the control of the polyhedrin and p10 promoters. In addition to the viral RNA polymerase, we are characterizing other factors that are responsible for the powerful very late transcription. We have found that a viral protein kinase is required for very late transcription. We have also generated a virus with a mutation in one of the genes encoding the viral RNA polymerase; this virus is defective in very late, but not late, transcription. In recent years, I have been helping to nurture the natural sciences at KU through my Associate Dean’s position. I am no longer accepting graduate or undergraduate students.
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