https://digitalcommons.unl.edu/plantpathpapers/117/
"Restriction Endonuclease Activity Induced by PBCV-1 Virus Infection of" by Yuannan Xia, Dwight...
An enzyme was isolated from a eucaryotic, Chlorella-like green alga infected with the virus PBCV-1 which exhibits type I1 restriction endonuclease activity....