Identification of a new promoter in the early region of the human papillomavirus type 16 genome

Transcription of the human papillomavirus type 16 (HPV-16) genome is contro lled by several promoters; the P-97 promoter is considered to be the main o ne. An additional promoter has been identified within the E7 ORF as well as an antisense promoter just upstream of the L2 ORF. The significance of the se promoters for early and late gene expression and their activity related to cell differentiation is not known in detail. Identification of two new, previously undescribed transcription start sites at nt 542 just upstream of the E7 ORF and at nt 611 within the E7 ORF is reported. The promoter respo nsible for the start site at nt 542 (P-542) was active in SiHa, HeLa and C3 3A cells. Very low promoter activity was found upstream of the nt 611 start site. The E7 protein has previously been shown to be synthesized from a po lycistronic mRNA encoding both the E6 and E7 proteins under the control of the P-97 promoter. The data reported in the present paper suggest that prom oter P-542 may control synthesis of the E7 oncoprotein from a monocistronic mRNA.