Protein synthesis related to epidermal differentiation.

作者：J. Kenneth Hoober, Isadore A. Bernstein · 发表于：Proceedings of the National Academy of Sciences · 年份：1966 · DOI：10.1073/pnas.56.2.594 · 被引用次数：73 · 研究领域：Transgenic Plants and Applications

DNA is synthesized in the epidermis of the newborn rat only in the cells of the basal or germinative layer,'-3 while RNA is produced in the spinous and granular layers as well.1' 4'' Radioautographic studies have shown that although amino acids are incorporated into the cells of all three layers6-8, there is a difference in the initial localization of certain amino acids.6Whereas tritiated leucine, phenylalanine, and methionine are first incorporated in the cells of the basal and lower spinous layers, tritiated glycine first appears more concentrated in the cells of the upper spinous and granular layers, and tritiated histidine first localizes in the cells of the upper layer.Methionine-S35 and cystine-S3 seem to be first incorporated in the inner layers.7' 8 This difference in the initial incorporation of amino acids and the histochemically demonstrated9 higher concentration of histidine in the granular relative to the other layers suggest that as epidermal cells differentiate during their migration from the basal layer toward the cornified layer, the synthesis of new and unusual proteins is initiated.In support of this hypothesis, fractions of epidermal protein have been isolated which are soluble in 8 M urea and dilute HC104, have high concentrations of glycine and histidine but little or no methionine, leucine, phenylalanine, or cyst(e)ine, and account for a major portion of the tritiated glycine and histidine initially incorporated in the epidermis under conditions of the...