Transcriptional Rearrangements Associated with Thermal Stress and Preadaptation in Baikal Whitefish (Coregonus baicalensis)

In this work, we describe the transcriptional profiles of preadapted and non-adapted one-month-old juvenile Baikal whitefish after heat shock exposure. Preadapted fish were exposed to a repeated thermal rise of 6 °C above the control temperature every three days throughout their embryonic development. One month after hatching, preadapted and non-adapted larvae were either kept at control temperatures (12 °C) or exposed to an acute thermal stress (TS) of 12 °C above the control temperature. In response to this acute stress, an increase in HSP gene expression (<i>HSP-30</i>, <i>HSP-40</i>, <i>HSP-47</i>, <i>HSP-70</i>, and <i>HSP-90</i>) and <i>TRIM16</i> was detected, independent of preadaptation. The expression levels of genes responsible for the response to oxygen levels, growth factors and the immune response, <i>HBA</i>, <i>HBB</i>, <i>Myosin VI</i>, <i>Myosin VII</i>, <i>MHC</i>, <i>Plumieribetin</i>, <i>TnI</i>, <i>CYP450</i>, and <i>LDB3</i> were higher in individuals that had previously undergone adaptation. Genes responsible for the regulation of metabolism, <i>MtCK</i>, <i>aFGF</i>, <i>ARF</i>, <i>CRYGB</i>, and <i>D-DT</i>, however, increased their activity in non-adapted individuals. This information on transcriptional profiles will contribute to further understanding of the mechanisms of adaptation of whitefish to their environment.