Differential Expression of Genes that Control Respiration Contribute to Thermal Adaptation in Redband Trout (Oncorhynchus mykiss gairdneri).
Bottom Line: Because increased water temperatures will reduce the dissolved oxygen available for fish, we hypothesized that adaptation to low oxygen environments would involve improved respiration through oxidative phosphorylation (OXPHOS).Supercomplexes may increase the efficiency of respiration because complexes I, III, and IV are brought into close proximity and oligomerization of complex V alters the macrostructure of mitochondria to improve respiration.Significant differences in gene expression patterns in response to heat stress in a common environment indicate that the response was not due to plasticity but had a genetic basis.
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Mentions: The COX6B2 isoform was upregulated in the desert fish in response to temperature. COX6B lies at the interface between monomers of complex IV and is one of the subunits that initiates the formation of the active, functional homodimer (Pierron et al. 2012). Different isoforms of nuclear-encoded COX subunits have been shown in many species to be important for the regulation of respiration and confer different activities on complex IV in different tissues and under different oxygen concentrations (Arnold 2012a; Pierron et al. 2012). It is possible that switching from the 6B1 to the 6B2 isoform here in gill tissue alters the formation of the homodimer, increases the stability of the complex itself or stabilizes interactions with other complexes, that is, supercomplexes (fig. 2) (Dudkina et al. 2008).Fig. 2.—
Affiliation: School of Biological Sciences, Washington State University firstname.lastname@example.org.