Figure 4.

HPV protein expression is not sufficient to promote Cx expression reprogramming (A) Schematic representation of the Ca²⁺-induced keratinocyte differentiation protocol. (B) Bar graph showing the relative mRNA expression of E2 and E6E7 viral genes in Ca-Diff keratinocytes over the differentiation time. Data represents mean ± s.e.m.; 3-4 independent experiments. *p < 0.05. (C) Representative Western blot of viral E6 protein expression and densitometric analysis of Cx43 protein expression in Ca²⁺-induced differentiated keratinocyte monolayer cell cultures over the differentiation time. GAPDH was used as loading control. Representative image of one experiment out of 3. Data in the densitometric analysis represent mean ± s.e.m.; control n=3, HPV18 n=3. (D) Bar graphs showing the relative mRNA expression of Cx43/GJA1 and Cx45/GJC1 genes in Ca-Diff keratinocytes over the differentiation time. Data represents mean ± s.e.m.; 4 independent experiments. (E, F) Representative Western blots of Cx43 (E) and Cx45 (F) expression in Ca²⁺-induced differentiated keratinocyte monolayer cell cultures over the differentiation time. Cyclophilin B (CypB) was used as a loading control. Bar graphs show the densitometric analyses (E, F), that correspond to the median +/- interquartile range from 2 independent experiments.