Analysis of the genome of molluscum contagiosum virus by restriction endonuclease analysis and molecular cloning.

Virions of molluscum contagiosum virus (MCV), a member of the poxviridae, were isolated directly from lesions of individual patients and characterized by restriction enzyme analysis. The comparative analysis of the cleavage patterns and Southern blot hybridization of 14 independently isolated virus samples revealed that MCV isolates can be classified into two different types. The majority of MCV isolated from clinically typical skin lesions (13 of 14) showed similar DNA cleavage patterns and were termed MCV type 1, whereas one isolate derived from a vaginal lesion showed a completely different DNA cleavage pattern and therefore was termed MCV type 2. For detailed investigation of the viral genome, a defined gene library of MCV DNA sequences was established. The Bam HI DNA fragments of the viral genome of MCV type 1 prototype isolate 1/80 was inserted into the bacterial plasmid vector pAT153. With the exception of terminal fragments (fragments A and B) of the viral genome, all other DNA fragments were cloned. All cloned Bam HI DNA fragments were individually identified by digestion of the recombinant plasmid DNA with different restriction enzymes and screened by hybridization of plasmid DNA to viral DNA.