FIG 1.

ΔIL mutant PsVs are noninfectious. (A) The 43-DQILQ-47 sequence is highly conserved across several types of HPV, including two low-risk (6 and 11) and four high-risk (16,18, 31, and 33). L2 protein sequences obtained from NCBI website (46). (B) Resulting amino acid sequences of PsVs after alanine scanning mutagenesis. ΔD mutant PsVs contain a substitution of L2 residue 43 with alanine. ΔQ mutant PsVs contain a substitution of L2 residue 44 with alanine. ΔI mutant PsVs contain a substitution of L2 residue 45 with alanine. ΔL mutant PsVs contain a substitution of L2 residue 46 with alanine. ΔIL mutant PsVs contain a substitution of L2 residues 45 and 46 with alanine. (C) Quantification of flow cytometry data for GFP expression. Pseudovirions were generated with plasmids where each individual amino acid in DQILQ sequence was substituted with an alanine by alanine scanning mutagenesis. Data is the average of three samples. Data is represented as mean ± SEM, n = 3. Individual statistical differences determined by Bonferroni’s post-test after significant ANOVA, α = 0.05, df = 8. (D–F) Flow cytometry data showing density plot with parent gate selecting HaCaT cells of interest (left) and histogram of cells within parent gate that express GFP (right) for (D) WT PsVs, (E) ΔIL mutant PsVs, and (F) ΔQ mutant PsVs.