Construction and characterization of a chimeric clone of parvovirus LuIII containing a substitution of its genomic termini for those of the prototype strain of parvovirus mice minute virus

Parvoviruses are small single-stranded DNA naked viruses with palindromic termini. These viruses are being considered as vectors for gene therapy. Mice Minute virus (MMv) and LuIII are two rodent parvoviruses which share over 80% DNA sequence identity, yet exhibit different encapsidation patterns. MMv encapsidates 99% minus strand DNA, whereas LuIII encapsidates equal amounts of plus and minus strand DNA. The termini of parvoviruses contain the cis elements necessary for the replication and encapsidation of viral DNA. It is unclear if the termini determine the nature of the DNA strand encapsidated. To study this possibility, a chimeric clone containing the LuIII protein coding region flanked by the termini of the prototype strain of MMv (MMvp) was constructed. This construct, called M-LuIII-M, produces a distinct restriction digestion pattern. Dideoxy DNA sequencing showed that M-LuIII-M contained sequences corresponding to the protein coding region of LuIII flanked by the MMvp termini.