The cleavage recognition signal is contained within sequences surrounding an a-a junction in herpes simplex virus DNA.
Herpesvirus genome maturation involves site-specific cleavage of viral DNA concatemers and encapsidation of unit-length molecules, processes that are apparently coupled. Here, applying a transfection-infection approach, we have investigated the arrangement of the DNA sequence elements involved in cleavage and shown that specific cleavage occurs independently of DNA replication. We show that the cis-acting signal for cleavage is located within a 179-bp fragment from across an a-a junction formed as part of the genome maturation process of herpes simplex virus 1. Plasmids carrying the 179-bp fragment are cleaved at the appropriate site even though they are unable to replicate in HSV-infected cells. When linked to an origin, the same 179-bp a-a fragment will replicate and package into progeny virus as a defective genome. Two highly conserved homologies, pac1 and pac2, that have been observed in all herpesviruses examined, including cytomegalovirus, Epstein-Barr virus, varicella-zoster virus, and herpes simplex virus 2 as well as the herpes simplex virus 1 genome, are contained within the 179-bp fragment. This suggests that a common mechanism is utilized for genome maturation in the herpesvirus group.
Nasseri
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Department of Microbiology and Immunology, Stanford University School of Medicine, California 94305.
Mocarski
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D000818:Animals; D001483:Base Sequence; D015139:Blotting, Southern; D003001:Cloning, Molecular; D004261:DNA Replication; D004262:DNA Restriction Enzymes; D004279:DNA, Viral / Q000235:genetics*; D010957:Plasmids; D018139:Simplexvirus / Q000235:genetics*; D014162:Transfection; D014709:Vero Cells
D004279:DNA, Viral; D004262:DNA Restriction Enzymes