DNase 2 is the main DNA-degrading enzyme of the stratum corneum.

PloS one (2011-03-11)
Heinz Fischer, Jennifer Scherz, Sandra Szabo, Michael Mildner, Charaf Benarafa, Alicia Torriglia, Erwin Tschachler, Leopold Eckhart
ABSTRACT

The cornified layer, the stratum corneum, of the epidermis is an efficient barrier to the passage of genetic material, i.e. nucleic acids. It contains enzymes that degrade RNA and DNA which originate from either the living part of the epidermis or from infectious agents of the environment. However, the molecular identities of these nucleases are only incompletely known at present. Here we performed biochemical and genetic experiments to determine the main DNase activity of the stratum corneum. DNA degradation assays and zymographic analyses identified the acid endonucleases L-DNase II, which is derived from serpinB1, and DNase 2 as candidate DNases of the cornified layer of the epidermis. siRNA-mediated knockdown of serpinB1 in human in vitro skin models and the investigation of mice deficient in serpinB1a demonstrated that serpinB1-derived L-DNase II is dispensable for epidermal DNase activity. By contrast, knockdown of DNase 2, also known as DNase 2a, reduced DNase activity in human in vitro skin models. Moreover, the genetic ablation of DNase 2a in the mouse was associated with the lack of acid DNase activity in the stratum corneum in vivo. The degradation of endogenous DNA in the course of cornification of keratinocytes was not impaired by the absence of DNase 2. Taken together, these data identify DNase 2 as the predominant DNase on the mammalian skin surface and indicate that its activity is primarily targeted to exogenous DNA.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
IGEPAL® CA-630, for molecular biology
Sigma-Aldrich
IGEPAL® CA-630, viscous liquid
Sigma-Aldrich
Bromophenol Blue
Sigma-Aldrich
Bromophenol Blue, ACS reagent
Supelco
IGEPAL® CA-630
Sigma-Aldrich
Deoxyribonuclease II from bovine spleen, Type V, essentially salt-free, lyophilized powder, ≥1,000 units/mg protein
Sigma-Aldrich
Deoxyribonuclease II from porcine spleen, Type IV, lyophilized powder, 2,000-6,000 Kunitz units/mg protein (biuret)