Differential gene expression indicates modulated responses to chronic and intermittent hypoxia in corallivorous fireworms (Hermodice carunculata)

Abstract

Climate models predict an increase in extent, frequency, and duration of marine hypoxia events in the twenty first century. A better understanding of organismal responses to hypoxia in individual species is a crucial step for predicting ecosystem responses. We experimentally subjected a common invertebrate, the bearded fireworm (Hermodice carunculata) to two levels of chronic hypoxia and, in a separate experiment, to intermittent hypoxia. We found components of the conserved hypoxia-inducible factor (HIF) pathway and show a modulated response to hypoxia depending on the severity of hypoxic stress: under mild hypoxia, only the HIF-1α subunit is upregulated, while expression of the other subunit, aryl hydrocarbon nuclear translator, only increases significantly at more severe hypoxia levels. The chronic trials revealed down-regulation of genes related to cell adhesion, transport, development and heme-binding, and up-regulation of genes related to glycolysis, oxygen binding, cell differentiation, digestive and reproductive function. The intermittent hypoxia trials revealed an upregulation of heme transporter activity during hypoxia, and our time series analysis characterized nine clusters of genes with similar expression patterns. Our findings suggest that H. carunculata is likely to tolerate, and be resilient to, predicted future hypoxia conditions.

Transcriptome Analysis of Crassostrea sikamea (♀) × Crassostrea gigas (♂) Hybrids Under Hypoxia in Occluded Water

“…The Notch family has four transmembrane receptors (Notch1-Notch4) and five ligands (Kadesch, 2004). In the previous studies, fibropellin-1, related to the Notch protein, drastically increased when post chronic hypoxia in the clam Ruditapes philippinarum (Nie et al, 2020) and the NOTCHs were upregulated in Hermodice carunculata under hypoxia (Grimes et al, 2021). Notch signaling was originally identified as a pleiotropic mediator of cell fate in invertebrates, which has recently emerged as an important regulator of immune cells (Radtke et al, 2013;Vanderbeck and Maillard, 2021).…”