Response of the JAK-STAT signaling pathway to oxygen deprivation in the red eared slider turtle, Trachemys scripta elegans

• We studied the regulation of JAK STAT pathway during anoxia in turtles.
• The JAK-STAT pathway was found to be activated in anoxic liver tissue.
• Downstream gene targets of activated STAT were also seen to increase in the liver.

The red-eared slider turtle, Trachemys scripta elegans, is a model organism commonly used to study the environmental stress of anoxia. It exhibits multiple biochemical adaptations to ensure its survival during the winter months where quantities of oxygen are largely depleted. We proposed that JAK-STAT signaling would display stress responsive regulation to mediate the survival of the red-eared slider turtle, Trachemys scripta elegans, during anoxic stress. Importantly, the JAK-STAT signaling pathway is involved in transmitting extracellular signals to the nucleus resulting in the expression of select genes that aid cell survival and growth. Immunoblotting was used to compare the relative phosphorylation levels of JAK proteins, STAT proteins, and two of its inhibitors, SOCS and PIAS, in response to anoxia. A clear activation of the JAK-STAT pathway was observed in the liver tissue while no significant changes were found in the skeletal muscle. To further support our findings we also found an increase in mRNA transcripts of downstream targets of STATs, namely bcl–xL and bcl-2, using PCR analysis in the liver tissues. These findings suggest an important role for the JAK-STAT pathway in exhibiting natural anoxia tolerance by the red-eared slider turtle.