Genome-Wide Identification of Hsp70 Genes in the Large Yellow Croaker (Larimichthys crocea) and Their Regulated Expression Under Cold and Heat Stress

Abstract

Heat shock proteins 70 (Hsp70) are required for key cellular processes and responses to environmental changes, however, there are an unknown number of hsp70 gene family members in the large yellow croaker (Larimichthys crocea). In the present study, 17 hsp70 genes were identified through the genome of the large yellow croaker. These genes are divided into seven evolutionarily distinct groups according to a phylogenetic tree. The orthologs of these hsp70 genes were found in humans and zebrafish. The expression patterns of the hsp70 gene family in the large yellow croaker under cold and heat stress were studied by examining transcriptome data. Six out of 17 genes were significantly unregulated or downregulated after cold or heat stress. There were two genes significantly upregulated and two genes downregulated in the liver after cold treatment, while after heat treatment, five genes were significantly upregulated, and no genes were significantly downregulated. Three expression patterns were detected: strictly heat-inducible hsp70, constitutively expressed and moderately heat-inducible hsp70, and constitutively expressed and less stress-dependent hsp70 genes. All the findings will contribute to a better understanding of the biological function of hsp70s in defending against thermal challenges.

A non-exhaustive survey revealed possible genetic similarity in mitochondrial adaptive evolution of marine fish species in the northwestern Pacific

“…Among them, species-specific patterns were detected in mitochondrial adaptive evolution, suggesting varied genetic mechanisms. In contrary, our previous studies consistently revealed that adaptive sites were detected in the posterior part of mitochondrial cytb gene ( Xu et al 2017 , 2018 ), to some extent suggesting potential genetic similarity in adaptive evolution of cytb gene. To confirm such potential similarity, here we collated population genetic studies of marine fish species in the northwestern Pacific based on mitochondrial cytb gene sequences and detect genetic adaptive sites by using population-based approaches.…”

“…Our previous study revealed codon 372 of cytb gene in S. marmoratus was situated in the last transmembrane domain, which is functionally important in the energy metabolism pathways ( Xu et al 2017 ). For the interspecific comparison between L. polyactis and L. crocea , as L. crocea is better adapted than L. polyactis in warmer environments ( Xiao et al 2009 ; Xu et al 2018 ), the detected interspecific substitutions might be also associated with the thermal adaptation of L. crocea . Therefore, codon 372 of cytb gene and its neighboring sites might be associated with metabolic processes and play important roles in thermal adaptation.…”

“…Considering that our major research field is population genetics of marine fish in the northwestern Pacific, we searched population genetics papers based on mitochondrial cytb gene sequences by using the search terms “population genetics”, “cytochrome b or cytb ”, “marine fish species” and “northwestern Pacific” in Google Scholar and China National Knowledge Infrastructure ( CNKI ) literature databases. Our previous studies revealed few genetic variations in the front half of the cytb gene ( Xu et al 2017 , 2018 ), suggesting the front part of the cytb gene is relatively conserved and unsuitable for population genetic analyses. Given that, papers only analyzing the front part of cytb gene sequences were excluded.…”

Genome-wide identification of Hsp70/110 genes in rainbow trout and their regulated expression in response to heat stress

“…Recent research has made significant progress in better understanding the mechanisms of action of Hsp70 and its co-partners, providing insights into the structural and functional characteristics of different members of the network. Genome-wide identification and annotation of Hsp70/110 gene family has been performed in some teleost, including Boleophthalmus pectinirostris ( Deng et al, 2019 ) , Paralichthys olivaceus ( Liu et al, 2019 ), Larimichthys crocea ( Xu, Xu & Han, 2018 ), and channel catfish ( Song et al, 2016 ). At the same time identification of the Hsp70/110 gene family has been performed in invertebrates, such as sea cucumber ( Gao et al, 2018 ).…”

Limits of temperature adaptation and thermopreferendum

“…It is noteworthy that even minor deviations from definitely tolerable temperatures between 20 °C and 30 °C evoked shock reactions in fish Danio rerio . Shock proteins expressed both in cold and heat stress were found not only in humans but also in various species of fish, including zebrafish [ 35 ]. With a slight increase in temperature in zebrafish, the expression of hsp70 mRNA can increase tenfold, however, the expression of the HSP70 protein increases only at potentially harmful temperatures [ 36 ].…”