Differential activation of MAPK during Müllerian duct growth and apoptosis: JNK and p38 stimulation by DES blocks tissue death.
To investigate the involvement of the mitogen-activated protein kinases (MAPKs) in c-Jun-mediated Müllerian duct (MD) differentiation, Western immunoblot with antibodies against c-Jun N-terminal kinase (JNK), extracellular signal-regulated kinases (ERK1 and 2), p38, phosphorylated JNK (p-JNK), and p-ERK were used to investigate these kinases in the left and right MDs (LMD and RMD, respectively) of female chicks. The content of these kinases in the LMD and RMD of various stages of embryos was detected by measuring their density in autoradiograms by a Spot-denso-program with Alpha Ease software. In the LMD, the growing embryonic sex tract, the amount of JNK increased from the 8th to 10th embryonic day and reached its highest at the 12th to 18th day. The content of ERK1, ERK2, and p38 remained at the same level throughout development. In the RMD, the apoptotic embryonic sex tract, the level of these four MAPKs showed a linear increase from the 8th to 10th day and then declined at the 12th day. Before the RMD entered the apoptotic stages (10th day of incubation), MAPKs were overexpressed. The findings following the application of p-MAPK antibodies, e.g., p-JNK and p-ERK, mirrored the result showing that differential activation of MAPKs existed in the LMD and RMD. When the RMD entered the apoptotic stages (13th to 18th day of incubation), the reduction in JNK activity was higher than that of the other three kinases. The apoptotic death of RMD was prevented by in vivo diethylstilbestrol treatment, which restored the level of JNK, p-JNK, and p38. No stimulatory effect was found for ERK and p-ERK.
Teng
C S
CS
Department of Anatomy, Physiological Sciences and Radiology, North Carolina State University, Raleigh, 27606, USA.
D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D015153:Blotting, Western; D002642:Chick Embryo; D004054:Diethylstilbestrol / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D009095:Mullerian Ducts / Q000166:cytology / Q000187:drug effects / Q000196:embryology* / Q000201:enzymology*; D048051:p38 Mitogen-Activated Protein Kinases
D004054:Diethylstilbestrol; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases