title: Identification of novel E6-E7 sequence variants of human papillomavirus 16.
abstract: The rate of evolution of the human papillomavirus 16 (HPV16) genome is low. However, the ability of the E6 oncoprotein to interact with distinct p53 variants causes selective pressure on the E6 gene. In addition, intratypic recombination events in the HPV16 E6 and E7 genes have been characterized as extraordinary phenomena during the evolutionary history of virus. In the present study, we identified two new sequence variants through nucleotide analysis of the E6-E7 region of the HPV16 genome. Maximum-likelihood and empirical Bayesian methods were used in order to identify positive selection at particular residues of the E6 and E7 genes. Using the single recombination breakpoint (SBP) method, we found evidence of recombination events in the E6 ORF. Nucleotide sequence analysis showed that the new sequence variants are phylogenetically distant from the other members of the population. Our results indicate that new evolutionary intermediates of HPV16 might be formed either though positive selective pressure or through recombination events by multiple infections with distinct HPV16 variants.
authors.affiliation: Microbiology-Virology Laboratory, Department of Biochemistry and Biotechnology, School of Health Sciences, University of Thessaly, Ploutonos 26 and Aiolou, 41221, Larissa, Greece.
authors.forename: D
authors.initials: D
authors.lastname: Tsakogiannis
authors.forename: Z
authors.initials: Z
authors.lastname: Kyriakopoulou
authors.forename: G
authors.initials: G
authors.lastname: Amoutzias
authors.forename: I G A
authors.initials: IG
authors.lastname: Ruether
authors.forename: T G
authors.initials: TG
authors.lastname: Dimitriou
authors.forename: E
authors.initials: E
authors.lastname: Panotopoulou
authors.forename: P
authors.initials: P
authors.lastname: Markoulatos
mesh_terms: D001483:Base Sequence; D001499:Bayes Theorem; D002584:Cervix Uteri / Q000821:virology; D003001:Cloning, Molecular; D019143:Evolution, Molecular; D005260:Female; D014644:Genetic Variation; D016679:Genome, Viral; D006115:Greece / Q000453:epidemiology; D052162:Human papillomavirus 16 / Q000235:genetics*; D006801:Humans; D016013:Likelihood Functions; D009856:Oncogene Proteins, Viral / Q000737:chemistry / Q000235:genetics*; D050725:Papillomavirus E7 Proteins / Q000737:chemistry / Q000235:genetics*; D030361:Papillomavirus Infections / Q000453:epidemiology / Q000821:virology*; D010802:Phylogeny; D012097:Repressor Proteins / Q000737:chemistry / Q000235:genetics*
chemical_list: C068651:E6 protein, Human papillomavirus type 16; D009856:Oncogene Proteins, Viral; D050725:Papillomavirus E7 Proteins; D012097:Repressor Proteins; C059731:oncogene protein E7, Human papillomavirus type 16