[DNA synthesis and content in the nuclei of epidermal cells of mice during their differentiation and specialization]

Abstract

Synthesis and content of DNA in the nuclei of differentiating cells of mouse skin epidermis was studied by using cytomorphometric, autoradiographic and cytophotometric methods. It has been shown that the cells of the keratinoid series divide only in the basal layer and contain 2-4c DNA. Keratinocytes of the thorny layer are mostly tetraploid, 2c cells are lacking. H4c and 8c cells comprise 12% of the population. In the keratinocytes of the granular layer DNA content is somewhat lower due to nuclei break down and conversion of cells into anucleate scale. Part of the melanocytes of the basal layer also contain 4c DNA. Highly specialized element of the basal layer Merkel and Langerhans cells are polyploid. Conclusion is drawn that DNA hyper-replication by multiplication of the whole genome is part of the development program of the population.