Mitogen-activated protein kinases and anoxia tolerance in turtles.
The response of two vertebrate mitogen-activated protein kinase (MAPK) family members, the extracellular signal-regulated kinases (ERKs) and c-Jun NH2-terminal kinases (JNKs), to anoxia exposure in vivo was examined in organs (liver, heart, kidney, brain, spleen) of the anoxia-tolerant adult turtle, Trachemys scripta elegans. ERKs activities rose during anoxia only in spleen (a 2.8-fold increase). JNK activity showed a significant increase only in liver (4-fold increase) after 5 hr of anoxic submergence but declined thereafter. Levels of the transcription factor c-Fos were strongly suppressed in liver, heart, and kidney of anoxia-exposed turtles, whereas levels increased 2-fold in anoxic brain. The effect of anoxia on c-Myc was organ-specific and variable with 2- and 1.5-fold increases in protein expression in kidney and brain, respectively, and a 60% decrease in anoxic spleen. These results for an anoxia-tolerant animal suggest the potential importance of the MAPKs and of the immediate-early genes (c-fos, c-myc) in mediating adaptive responses to oxygen deprivation.
Greenway
S C
SC
Faculty of Medicine, University of Manitoba, Winnipeg, Canada.
Storey
K B
KB
D000220:Adaptation, Biological / Q000502:physiology*; D000818:Animals; D000860:Hypoxia; D008099:Liver / Q000201:enzymology; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D016760:Proto-Oncogene Proteins c-fos / Q000096:biosynthesis; D016271:Proto-Oncogene Proteins c-myc / Q000096:biosynthesis; D013997:Time Factors; D014018:Tissue Distribution; D014157:Transcription Factors / Q000032:analysis; D014426:Turtles / Q000502:physiology*
D016760:Proto-Oncogene Proteins c-fos; D016271:Proto-Oncogene Proteins c-myc; D014157:Transcription Factors; D020928:Mitogen-Activated Protein Kinases