Green-striped burrowing frogs, Cyclorana alboguttata, survive droughts by 
entering a metabolic depression called aestivation, characterised by a reduction 
in resting oxygen consumption by 80%. Aestivation in C. alboguttata is manifest 
by transcriptional silencing of skeletal muscle bioenergetic genes, such as NADH 
ubiquinone oxidoreductase 1, ATP synthase and superoxide dismutase 2. In this 
study, we hypothesised that aestivation is associated with epigenetic change in 
frog muscle. We assessed mRNA transcript abundance of seven genes that code for 
proteins with established roles in epigenetically-mediated gene silencing 
[transcriptional co-repressor SIN3A, DNA (cytosine-5-) methyltransferase 1, 
methyl CpG binding protein 2, chromodomain helicase DNA binding protein 4, 
histone binding protein rbbp4, histone deacetylase 1 and nuclear receptor 
co-repressor 2] using qRT-PCR. These seven genes showed a modest (1.1-3.5-fold) 
but coordinated upregulation in 6-month aestivating muscle. This reached 
significance for SIN3A and DNA cytosine-5-methyltransferase 1 in standard 
pair-wise comparisons (p < 0.05), and the candidates as a whole when analysed by 
Fisher's combined probability test (p < 0.01). These data are consistent with 
the hypothesis that the transcriptional silencing and metabolic depression that 
occurs during seasonal dormancy are associated with chromatin remodelling, and 
present a novel example of an environmentally induced epigenetic modification in 
an adult vertebrate.