Distribution of the extended family of protein kinase C isoenzymes in fetal organs of mice: an immunohistochemical study

Abstract

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 different manufacturers, were employed in this study. The specificity of the antisera was tested by immunoblotting experiments using whole fetal mouse extracts. Immunohistochemistry was carried out by means of an alkaline phosphatase-conjugated secondary antibody. Analysis of fetal mouse longitudinal cryostat sections stained with the antibodies demonstrated a distinct distribution of protein kinase C isoforms in the tissues. Protein kinase C-α and C-βI were present in all tissues examined, whereas the C-βII isoform was absent in the lung and the liver. Protein kinase C-γ was identified in brain, spinal ganglia, and adrenal gland. The C-ε isoenzyme was abundantly expressed in spinal ganglia and in the smooth muscle cells of the bronchial wall. Antisera to C-ζ and C-η isoforms heavily stained liver, kidney, and spinal ganglia, whereas the C-θ isozyme was mainly detected in brain, stomach and kidney. Thus, protein kinase C-α, C-βI, C-βII, C-ζ, C-η and C-θ were the isoforms present in many of the organs investigated. The two sets of antibodies gave slightly different results that might be ascribed to the different epitopes recognized by the antisera. One set of antisera was employed to investigate the distribution of the isoforms in selected organs from an earlier developmental age (15 days) and from adult animals. Both qualitative and quantitative differences were seen in comparison with the same organs from a 17-day fetus.