technical paper
The protein-protein interaction network architecture of the environmental stress response in zebrafish embryos
keywords:
systems biology
network evolution
stress response network
Protein-protein interaction (PPI) network topology determines properties of genes, such as expression levels, or levels of evolutionary constraint. When genes are central to a network they are more likely to be conserved and highly expressed, whereas genes that are able to change in response to evolutionary pressures but expressed at lower levels are located on the periphery of the network. We used transcriptomic data of zebrafish (Danio rerio) embryos to compare the PPI properties of the response to two environmental stressors (heat, UVR and combination). We show that genes with stress response Gene Ontology are situated centrally to the PPI network. The transcriptomic response to heat occupied central and peripheral positions within the reference network, whereas UV response occupied central and intermediate positions. Prefacing UVR with heat led to a downshift of DEGs, which could explain the hormetic effect of heat stress. In addition, when only considering genes specific to each stressor, heat responsive DEGs were located more peripherally, and uniquely UV responsive DEGs were located intermedially in the PPI. Overall, these results support the idea that the stress response must have both conserved and derived aspects, in order to respond to stress generally but to also allow for specialisation, which we show to be reflected in the PPI network architecture. These properties can aid in better understanding the organismal response to diverse and co-occurring environmental stressors.