Restriction Endonuclease Activity Induced by PBCV-1 Virus Infection of a Chlorella-Like Green Alga

Authors

Yuannan Xia, University of Nebraska-LincolnFollow
Dwight Burbank, University of Nebraska-Lincoln
Lothar Uher, Bethesda Research Laboratories, Life Technologies, Inc., Gaithersburg, Maryland
Dietrmar Rabussay, Bethesda Research Laboratories, Life Technologies, Inc., Gaithersburg, Maryland
James L. Van Etten, University of Nebraska-LincolnFollow

Date of this Version

5-1986

Comments

Published in MOLECULAR AND CELLULAR BIOLOGY, Ma y 1986, p. 1430-1439, Vol. 6, No. 5. Copyright 1986, American Society for Microbiology. Used by permission.

Abstract

An enzyme was isolated from a eucaryotic, Chlorella-lie green alga infected with the virus PBCV-1 which exhibits type II restriction endonuclease activity. The enzyme recognized the sequence GATC and cleaved DNA 5' to the G. Methylation of deoxyadenosine in the GATC sequence inhibited enzyme activity. In vitro the enzyme cleaved host Chlorella nuclear DNA but not viral DNA because host DNA contains GATC and PBCV-1 DNA contains G^mATC sequences. PBCV-1 DNA is probably methylated in vivo by the PBCV-1-induced methyltransferase described elsewhere (Y. Xia and J. L. Van Etten, Mol. Cell. Biol. 6:1440-1445). Restriction endonuclease activity was first detected 30 to 60 min after viral infection; the appearance of enzyme activity required de novo protein synthesis, and the enzyme is probably virus encoded. Appearance of enzyme activity coincided with the onset of host DNA degradation after PBCV-1 infection. We propose that the PBCV-1-induced restriction endonuclease participates in host DNA degradation and is part of a virus-induced restriction and modification system in PBCV-1-infected Chlorella cells.