SEQUENCE-ANALYSIS OF A MOLLUSCUM-CONTAGIOSUM VIRUS-DNA REGION WHICH INCLUDES THE GENE ENCODING PROTEIN-KINASE 2 AND OTHER GENES WITH UNIQUEORGANIZATION

The nucleotide sequence of a near left-terminal region from the genome of Molluscum contagiosum virus subtype I (MCVI) was determined. This region was contained within three adjacent BamHI fragments, designated L (2.4 kilobases (kb)), M (1.8 kb), and N (1.6 kb). BamHI cleavage of MCVI DNA produced another 1.6-kb fragment (N'), which had been mapped 30-50 kb from the L,M region. The MCVI restriction fragments were clo ned and end-sequenced. The N fragment that maps at the L,M region was identified by the polymerase chain reaction, using primers devised fro m the sequence of each fragment. The results from this analysis led to establish the relative position of these fragments within the MCVI ge nome. The analysis of 3.6 kb of DNA sequence revealed the presence of ten open reading frames (ORFs). Comparison of the amino acid sequence of these ORFs to the amino acid sequence of vaccinia virus (VAC) prote ins revealed that two complete MCVI ORFs, termed N1L and L1L, showed h igh degree of homology with VAC F9 and F10 genes, respectively. The F1 0 gene encodes a 52-kDa serine/threonine protein kinase (protein kinas e 2), an essential protein involved in virus morphogenesis. The MCVI h omologue (L1L) encoded a putative polypeptide of 443 aa, with a calcul ated molecular mass of 53 kDa, and 60.5/30.2% sequence identity/simila rity to VAC F10. The MCV N1L (213 aa, 24 kDa) showed 42.6/40.6% amino acid sequence identity/similarity to VAC F9, a gene of unknown functio n encoding a 24-kDa protein with a hydrophobic C-terminal domain, whic h was conserved in MCVI. The genomic arrangement of MCVI N1L and L1L w as equivalent to that of the vaccinia and variola virus homologues. Ho wever, the ORFs contained within MCVI fragment M (leftward) showed no homology, neither similarity in genetic organization, to the genes enc oded by the corresponding regions of vaccinia and variola viruses.