IHC analysis showed that HDAC2 was expressed in all layers of Hdac1Δ/Δep Hdac2Δ/+epidermismindicatinging that the developmental defects of Hdac1Δ/Δep Hdac2Δ/+ep mice were not due to restricted HDAC2 expression patterns (Supplementary Figure S2A).
We found no differences in the expression levels of K10, loricrin, and filaggrin among control, Pofut1/Tgfb3-Cre, and Rbpj/Tgfb3-Cre mice, while an expansion of K14-expressing cell layers (Figure 3B) and an increase of Ki67-positive signal in the suprabasal K14-expressing keratinocytes (Figure 3C) was detected in the Rbpj/Tgfb3-Cre epidermis, indicating a hyperproliferative state.
Studies of adult mice carrying conditional deletions of either plectin or the integrin subunit α6 in the epidermis indicated that in vivo HDs are very stable structures, exhibiting a very low turnover (Ackerl et al. 2007; Niculescu et al. 2011).
Lack of ΔNp63 in Flores' model mainly phenocopied the gross morphology of the ΔNp63 mouse epidermis described by Romano et al. (hereafter indicated as ΔNp63gfp/gfp), which is partially similar to the phenotypes of both of the p63−/− mouse models that lack all of the p63 isoforms.
It is also noteworthy that SPREADs were also observed in the epidermis of backskin, indicating that SPREADs are generally observed in mouse epidermis.
In summary, with the exception of modest increases in epidermal proliferation in 4OHT-treated IKOα mice, the acute single ablation of C/EBPα or C/EBPβ in adult mouse epidermis results in a phenotype similar to the germline knockout phenotype [25], [26], indicating developmental compensatory events do not have a major role in masking the postnatal germline knockout phenotype.
The tissue specific ablation of the Notchl receptor in mouse epidermis leads to hyperplasia in the epidermis, the development of tumors and an increased susceptibility to chemical carcinogens – thus indicating that Notch acts as a tumor suppressor in mammal skin [ 40].
TC45 was also primarily localized in the cytoplasm of mouse epidermis (data not shown).
Since low H4 acetylation was common in stem cells in human interfollicular epidermis (Fig. 1), we examined whether this was also the case in mouse epidermis (Fig. 3A D).
After this, the two lists of differentially expressed genes were crossed, thereby selecting genes that were either down- or up-regulated both in GATA3−/− epidermis (when compared to WT mouse epidermis), as wells as in lesional psoriatic epidermis (when compared to non-lesional epidermis).
