Isolation and Characterization of Epidermal DNA and RNA from Guinea Pig Skin

DNA and RNA were isolated from mammalian epidermis in a relatively small scale procedure. The high purity and native state of the DNA isolated is reflected by its molar absorptivity E (P), its thermal hyperchromicity and its hyperchromicity upon DNase treatment and by its sedimentation profile as well as by its profile in a cesium chloride density gradient. The very low content of protein and RNA, as well as the data of DNA determination, indicate that this method permits the isolation of a highly purified product. This is further substantiated by the determination of UV absorption spectra and by analysis of the base composition.The mammalian skin DNA showed the following properties: Mol. wt. = 3.7 × 106; melting point = 80.7°C; E(P) = 6150; molar N/P ratio = 3.67; thermal hyperchromicity = 40.9%; hyperchromicity upon DNase treatment = 38%; sedimentation coefficient = 16.3; boyant density in CsCl = 1.6969 g/cm3. The guanine, cytosine, adenine and thymine content was 19.0, 20.5, 29.0 and 28.5 moles% respectively. Epidermal RNA was isolated and characterized in terms of phosphorus content, RNA content, and hydrolysis by RNase. By our results, a minimum content of 3mg DNA per 1000mg epidermis (minus stratum corneum) appears reasonable