DISTRIBUTION OF THE EXTENDED FAMILY OF PROTEIN-KINASE-C ISOENZYMES INFETAL ORGANS OF MICE - AN IMMUNOHISTOCHEMICAL STUDY

Using isoenzyme-specific antisera, we have studied the distribution of protein kinase C isoforms in fetal mouse organs at the developmental age of 17 days. Two different sets of antibodies, produced by differen t manufacturers, were employed in this study. The specificity of the a ntisera was tested by immunoblotting experiments using whole fetal mou se extracts. Immunohistochemistry was carried out by means of an alkal ine phosphatase-conjugated secondary antibody. Analysis of fetal mouse longitudinal cryostat sections stained with the antibodies demonstrat ed a distinct distribution of protein kinase C isoforms in the tissues . Protein kinase C-alpha and C-beta I were present in all tissues exam ined, whereas the C-beta II isoform was absent in the lung and the liv er. Protein kinase C-gamma was identified in brain, spinal ganglia, an d adrenal gland. The C-epsilon isoenzyme was abundantly expressed in s pinal ganglia and in the smooth muscle cells of the bronchial wall. An tisera to C-xi and C-eta isoforms heavily stained liver, kidney, and s pinal ganglia, whereas the C-theta isozyme was mainly detected in brai n, stomach and kidney. Thus, protein kinase C-alpha, C-beta I, C-beta II, C-xi, C-eta and C-theta were the isoforms present in many of the o rgans investigated. The two sets of antibodies gave slightly different results that might be ascribed to the different epitopes recognized b y the antisera. One set of antisera was employed to investigate the di stribution of the isoforms in selected organs from an earlier developm ental age (15 days) and from adult animals. Both qualitative and quant itative differences were seen in comparison with the same organs from a 17-day fetus.