Transcriptional expression levels of cell stress marker genes in the pacific oyster Crassostrea gigas exposed to acute thermal stress
Résumé
Abstract During the annual cycle, oysters are exposed to seasonal slow changes in temperature, but during emersion at low tide on sunny summer days, their internal temperature may rise rapidly, resulting in acute heat stress. We experimentally exposed oysters to a 1-h acute thermal stress and investigated the transcriptional expression level of some genes involved in cell stress defence mechanisms, including chaperone proteins (heat shock proteins Hsp70, Hsp72 and Hsp90 (HSP)), regulation of oxidative stress (Cu-Zn superoxide dismutase, metallothionein (MT)), cell detoxification (glutathione 5-transferase sigma, cytochrome P450 and multidrug resistance (MDR1)) and regulation of the cell cycle (p53). Gene mRNA levels were quantified by reverse transcription-quantitative polymerase chain reaction and expressed as their ratio to actin mRNA, used as a reference. Of the nine genes studied, HSP, MT and MDR1 mRNA levels increased in response to thermal stress. We compared the responses of oysters exposed to acute heat shock in summer and winter and observed differences in terms of magnitude and kinetics. A larger increase was observed in September, with recovery within 48 h, whereas in March, the increase was smaller and lasted more than 2 days. The results were also compared with data obtained from the natural environment. Though the functional molecule is the protein and information at the mRNA level only has limitations, the potential use of mRNAs coding for cell stress defence proteins as early sensitive biomarkers is discussed.
Mots clés
heat stress
marker gene
nonhuman
nucleotide sequence
oxidative stress
oyster
priority journal
quantitative analysis
reverse transcription polymerase chain reaction
seasonal variation
summer
temperature stress
winter
animal
gene expression profiling
genetics
heat shock response
metabolism
Pacific Ocean
season
temperature
Crassostrea gigas
Ostreidae
Animals
Biological Markers
Crassostrea
Gene Expression Profiling
Heat-Shock Response
RNA
Messenger
Seasons
Temperature
actin
biological marker
copper zinc superoxide dismutase
cytochrome P450
glutathione transferase
heat shock protein 70
heat shock protein 72
heat shock protein 90
messenger RNA
metallothionein
multidrug resistance protein 1
protein p53
article
cell cycle regulation
cell stress
controlled study
ebb tide
environmental temperature
gene expression
genetic transcription