Figure 2.

Loss of RNase H2 in the epidermis results in spontaneous type I IFN response and inflammation

a) Representative Rnaseh2^EKO back skin section (age 10–12 weeks) immunostained for CD45 (purple) for identification of hematopoietic cells (see supplementary material for detailed histopathological findings). Original magnification x200.

b) Quantification of CD45⁺ leukocytes in single cell suspensions prepared from the epidermal compartment of back skin from 10–12 week-old Rnaseh2^EKO (EKO) mice (n=10) and control (Rnaseh2b^FL/FLCre-negative) littermates (n=9). Mean and SD, ***p<0.0001.

c) Comparison of ISG transcript levels determined by qRT-PCR in RNA extracted from total epidermis of 10–12 and 20 week-old Rnaseh2^EKO (EKO) mice to the mean obtained for control (Rnaseh2b^FL/FLCre-negative) littermates (10–12 wk n=6, 20 wk n=3) which was set to 1 (dotted line).10–12 weeks: **p=0.0018 (Oasl1), *p=0.0105 (Ifi44), *p=0.0162 (Viperin), 20 weeks: *p=0.0242 (Oasl1), **p=0.0061 (Ifi44), *p=0.0246 (Viperin).

d) Comparison of gene expression profiles of FACS-purified CD45⁺ leukocytes from epidermis of 12 week-old Rnaseh2^EKO (EKO) mice (n=7) and control (Rnaseh2b^FL/FLCre-negative) littermates (n=6) based on RNA sequencing. Significantly (p<0.05) deregulated genes in black. Significantly deregulated ISGs in red.

e) Macroscopic phenotype of an 11 week-old Ifnar1^−/−Rnaseh2^EKO mouse (note hyperpigmentation of ears, tail and paws, and almost complete hair loss) and a control (Ifnar1^−/−Rnaseh2b^FL/FLCre-negative) littermate.

f) Quantification of CD45⁺ leukocytes in the epidermis of 10–12 week-old Ifnar1^−/−Rnaseh2^EKO (EKO) mice (n=7) and control (Rnaseh2b^FL/FLCre-negative) littermates (n=7). Mean and SD, ***p=0.0009.

g) Flow cytometric quantification of hair follicle stem cell populations in back skin of 10–12 week-old Ifnar1^−/−Rnaseh2^EKO mice (n=7) and control (Ifnar1^−/−Rnaseh2b^FL/FLCre-negative) littermates (n=7). See Fig.S1f for gating; mean and SD, ***p<0.0001, *p=0.0209.