Meeting Abstract

P1.213  Wednesday, Jan. 4  Seasonal expression of cytochrome c oxidase and citrate synthase genes in the Eastern red spotted newt (Notophthalmus viridescens viridescens) MARQUAND, T.H.*; BERNER, N.J.; Sewanee: The University of the South; Sewanee: The University of the South nberner@sewanee.edu

Eastern red spotted newts are active in the winter. Previous work has shown that cold-acclimated newts (8°C) have higher activity (per mg wet tissue weight) of cytochrome c oxidase (CCO) and citrate synthase (CS) in skeletal muscle than warm-acclimated newts (26°C). However, their skeletal muscle has a lower mitochondrial density when cold-acclimated than when warm-acclimated and cristea surface area does not change. This experiment was performed to test the hypothesis that an increase in the gene expression of CCO and CS in winter newts could compensate for the decrease in mitochondrial density to increase CCO and CS activity. This hypothesis was tested by comparing the expression of two CCO subunits and CS between summer and winter newts using real-time polymerase chain reaction (rtPCR). We isolated RNA from skeletal muscle, heart and liver from 10 summer-caught newts and 10 winter-caught newts. We used the 16s rRNA as the endogenous control for the mitochondrial gene COX 1, and 28s rRNA gene as the endogenous control for the nuclear genes COX 5a and CS. We found no significant difference in expression of COX1 across seasons in any tissue. Analysis of COX5a and CS gene expression is continuing. If there is no difference in the expression of these genes between seasons, then we will continue to investigate other factors that could impact their activity seasonally.