|dc.description.abstract||Crucian carp are unusual among vertebrates in surviving extended periods in the complete absence of molecular oxygen.
During this time cardiac output is maintained though these mechanisms are not well understood. Using a high-density
cDNA microarray, we have defined the genome-wide gene expression responses of cardiac tissue after exposing the fish at
two temperatures (8 and 13uC) to one and seven days of anoxia, followed by seven days after restoration to normoxia. At
8uC, using a false discovery rate of 5%, neither anoxia nor re-oxygenation elicited appreciable changes in gene expression.
By contrast, at 13uC, 777 unique genes responded strongly. Up-regulated genes included those involved in protein turnover,
the pentose phosphate pathway and cell morphogenesis while down-regulated gene categories included RNA splicing and
transcription. Most genes were affected between one and seven days of anoxia, indicating gene regulation over the
medium term but with few early response genes. Re-oxygenation for 7 days was sufficient to completely reverse these
responses. Glycolysis displayed more complex responses with anoxia up-regulated transcripts for the key regulatory
enzymes, hexokinase and phosphofructokinase, but with down-regulation of most of the non-regulatory genes. This
complex pattern of responses in genomic transcription patterns indicates divergent cardiac responses to anoxia, with the
transcriptionally driven reprogramming of cardiac function seen at 13uC being largely completed at 8uC.||nb_NO