Expression of Protein Kinase C Isoform mRNAs in the Developing Rat Heart

BACKGROUND AND OBJECTIVES: Protein kinase C (PKC) is known to be related with development of various cells. In the heart, each isoform reacts differentially against agonists and the reaction changes during development. In this study, the roles of PKC isoforms (alpha, beta, gamma, delta, epsilon, zeta) were investigated through the localization of mRNA expression in the developing rat heart with in situ hybridization histochemistry. MATERIALS AND METHOD: The mRNA expression pattern of PKC isoforms (alpha, beta, gamma, delta, epsilon, zeta) was investigated with in situ hybridization histochemistry in developing and adult rat hearts. Whole body parasagittal sections were used for embryonal day 14 (E14), E16, E18 and heart sections were used for just born (P0), postnatal day 7 (P7), P14, P21 and adult rat. RESULTS: The expression of PKC alpha was found from E14, peaked at P7, and gradually decreased to adult level. The expression of PKC beta was observed from P14, peaked at P21, and decreased to adult level. The expression of PKC delta in the heart was observed from E14, peaked at P0, and abruptly disappeared at P14. The expression of PKC epsilon was observed from E14, peaked at P0, after that gradually decreased and disappeared at adult rat heart. The expression of PKC gamma and zeta was not found from any stage of developing rat heart. CONCLUSION: From these results, it is suspected that each PKC isoform may be differentially related with development of heart. The strong expression of PKC alpha, delta, epsilon around perinatal period, rapidly developing stage, suggests that PKC alpha, delta, epsilon may be related with rapid development of rat heart. And the late postnatal expression of PKC beta suggests that PKC beta may be related with maturation of rat heart.

Developmental mRNA Expression of Cellular Retinoic Acid Binding Protein l and l in Rat

PURPOSE: Retinoic acid (RA) is well known as a potent teratogenic agent in both deficiency and excess. Cellular retinoic acid binding proteins (CRABPs) are involved in RA. We carried this study in order to determine the possible relations of CRABPs with RA-induced teratogenesis through observation of the expression patterns of CRABP l and ll in developing rats. METHODS: 35S-labeled RNA probes were synthesized using SP6-RNA polymerase in CRABP l and T7-polymerase in CRABP ll. The distribution of CRABP l and ll transcripts analyzed by in situ hybridization of rat embryosections from day 12 to 19, and postnatal brains from day 1 to 14. RESULTS: The CRABP ll transcripts were more widely distributed than CRABPl distribution, however, the relative level of CRABPl transcripts were higher than CRABP ll. The CRABP l mRNA transcripts showed its highest expression on the 16th day of gestation and these distribution correlated well with structures known to be targets of RA-induced teratogenesis. CRABP ll transcripts were expressed in brain vesicle, spinal cord, head, face, tongue and genital tubercle and also found in the structures which are not involved in RA-induced teratogenesis. CONCLUSION: These results suggest the possible involvement of both CRABPs in the RA-induced teratogenesis. However, CRABP l may have more specific roles than CRABP ll which may play a role through a different mechanism.