Isolation and characterization of a variant of human papillomavirus type 11 from a nasal inverting (Schneiderian) papilloma.

We have previously reported the presence of a variant of human papillomavirus (HPV) type 11 in a nasal inverting papilloma [Respler et al., 1987]. In the present study, we have cloned molecularly the DNA of this variant at its unique restriction enzyme Bam HI site into lambda BF101 phage. Restriction enzyme mapping and DNA sequencing revealed that the genome of this virus contained an extra 531 base pair (bp) which was the repeat of most of the noncoding region (ncr) of HPV 11. Insertion of transcriptional control elements, including the repeated sequence, in front of the chloramphenicol acetyltransferase (CAT) gene resulted in a 5- to 30-fold increase in expression in transfected cells, as compared to the constructs containing a single ncr of HPV 11. This increased expression was due to enhanced levels of CAT RNA the synthesis of which is initiated by the viral promoter element.