FIG 7 .

Expression and function of hnRNP D0B and hnRNP A/B in HFK18 keratinocytes. (A) Expression of hnRNP D0B, hnRNP A/B, RFC2, RFC3, and RFC4 in HFK18 cells under conditions of calcium-mediated differentiation. HFK18 cells were incubated with calcium-free EpiLife medium (no FBS) supplemented with 1× HKGS for 24 h, followed by induction of cell differentiation for 48 or 96 h with 3 mM Ca²⁺ EpiLife medium (5% FBS, 1× HKGS, 3 mM CaCl₂) before total protein sample preparation was performed for Western blotting of individual proteins with corresponding antibodies. Involucrin served as a keratinocyte differentiation marker and β-tubulin and hnRNP C1/C2 as loading controls. (B) Nuclear and cytoplasmic distribution of hnRNP D0B and hnRNP A/B by cell fractionation of HFK18 cells under low- or high-calcium conditions. See details in the panel A legend. (C and D) Knockdown of hnRNP D0B and hnRNP A/B expression in HFK18 cells promotes HPV18 late promoter activity. The cells with efficient knockdown of the corresponding protein (C) were cotransfected by plasmid pXHW16 and pRL-TS and examined for HPV18 late promoter activity in the presence of 3 mM calcium (D). Nonspecific (NS) siRNA served as a control. hnRNP A/B and hnRNP D0B siRNA knockdown efficiency in HFK18 cells (C) was examined by Western blotting.