Cloning and analysis of human papillomavirus type 18 codon optimized Flag-tagged E2 protein

Abstract

Human papillomaviruses (HPVs) are highly prevalent pathogens, which are associated with wide variety of disorders. HPVs encode nine proteins. E2 protein is a key regulator of HPV life cycle. The E2 proteins function in initiation of DNA replication, transcriptional regulation and partitioning of viral genome. However, E2 proteins are expressed at very low level, which significantly complicates studies of these proteins. In order to increase expression of HPV18 E2 protein, codon optimized sequence of E2 was inserted to the pCMV-Flag-4 vector, which contains Flag epitope. Flag-tag potentially may influence E2 protein properties and expression level. Results have shown that codon optimization of E2 protein encoding sequence increased the expression level of HPV18 E2 proteins in 293FT cells; codon optimized E2-Flag protein supported replication of HPV18 E2- deficient genome in U2OS cells. New HPV18 E2c.o.pCMV-Flag construct is functional.