Abstract
The distribution of ribonuclease and deoxyribonuclease activities was examined by substrate film methods in rat and mouse skin, mouth, tongue, and oesophagus epithelia and in skin papillomas.
In the various types of stratified squamous epithelia, nuclease activity was found to be localized in well-defined perinuclear zones in cells of the Malpighian layer. The activity in these sites increases from the lower to the upper layers and a strong band reaction corresponds to the limit between the non-keratinized and keratinized cell layers.
Apparently, the nucleases play an important role in the keratinization process in being responsible for the disappearance of nucleic acids which accompanies other radical changes taking place in transitional cells at the surface of the Malpighian layer.