IDENTIFICATION OF FIBROUS PROTEINS IN FETAL RAT EPIDERMIS BY ELECTROPHORETIC AND IMMUNOLOGICAL TECHNIQUES

[摘要] Proteins (2) were identified in extracts of fetal rat skin which are related to the 2 major fibrous proteins of newborn rat stratum corneum. The relative amount of these proteins increased daily from the 16th-20th day (d) of gestation when judged by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis and immunoelectrophoresis using antibody to the purified fibrous protein. Two-dimensional analysis by SDS-polyacrylamide gel electrophoresis and immunoelectrophoresis demonstrated that these 2 proteins are the only cross-reactive species in the fetal skin from 16d-19d development. Some additional lower molecular weight components were detected at 20d and 21d. In double-diffusion analysis, cross-reactive proteins in 19d fetal extracts showed partial identity but had fewer antigenic sites than proteins in 20d extracts. The 20d protein showed a reaction of identity with purified newborn fibrous protein. Immunofluorescence studies on fetal skin support the presence of cross-reacting components at 16d development related to the newborn fibrous protein. Intensity of fluorescence increases at 18d and 20d in the spinous and granular cell cytoplasm and in the keratohyaline granules. The stratum corneum, first seen at 20d, was intensely fluorescent. The cellular localization and time of appearance of the cross-reactive proteins suggest that they may be associated with tonofilaments.