Meeting Abstract
Adult Eastern red spotted newts remain active in winter. Our previous research shows that acclimation to winter conditions includes an increase their metabolic rate and in the activity of membrane-bound metabolic enzymes, an adjustment of overall membrane fatty acid composition toward more polyunsaturation, and modified fatty acid content of cardiolipin (CL). Of particular interest here are the higher skeletal muscle cytochrome c oxidase (CCO) activity and the change in CL structure in winter newts. The skeletal muscle of winter newts presents a predominant CL with a lower mass ratio (1447.97 m/z) in comparison to summer newts (1449.99 m/z). Cardiolipin plays a role in maintaining mitochondrial membrane shape, and is thought to facilitate structural changes necessary for CCO activity. After biosynthesis, CL is modified into an active form by the phospholipid transacylase called tafazzin, which is encoded by the TAZ gene. Our experiment was conducted to test the hypothesis that TAZ gene expression levels change with season (increase in winter), which would correlate with CL fatty acid makeup and changes in CCO activity, providing a possible mechanism for acclimation of these characteristics. Newts were collected in winter and summer, euthanized, and skeletal muscle and liver tissue was stored in RNAlaterTM. RNA was isolated from approximately 0.04 g tissue. The RNA samples were diluted to similar concentrations for conversion to cDNA. Quantitative real time PCR was run to compare TAZ gene expression in winter and summer newts. Preliminary data from 8 summer and 10 winter newt liver tissue samples show a significant (p = 0.017) increase in TAZ expression in winter. We expect TAZ levels to be up-regulated in winter newt skeletal muscle tissue as well.
