Abstract
BackgroundTemperature is one of key environmental parameters that affect the whole life of fishes and an increasing number of studies have been directed towards understanding the mechanisms of cold acclimation in fish. However, the adaptation of larvae to cold stress and the cold-specific transcriptional alterations in fish larvae remain largely unknown. In this study, we characterized the development of cold-tolerance in zebrafish larvae and investigated the transcriptional profiles under cold stress using RNA-seq.ResultsPre-exposure of 96 hpf zebrafish larvae to cold stress (16°C) for 24 h significantly increased their survival rates under severe cold stress (12°C). RNA-seq generated 272 million raw reads from six sequencing libraries and about 92% of the processed reads were mapped to the reference genome of zebrafish. Differential expression analysis identified 1,431 up- and 399 down-regulated genes. Gene ontology enrichment analysis of cold-induced genes revealed that RNA splicing, ribosome biogenesis and protein catabolic process were the most highly overrepresented biological processes. Spliceosome, proteasome, eukaryotic ribosome biogenesis and RNA transport were the most highly enriched pathways for genes up-regulated by cold stress. Moreover, alternative splicing of 197 genes and promoter switching of 64 genes were found to be regulated by cold stress. A shorter isoform of stk16 that lacks 67 amino acids at the N-terminus was specifically generated by skipping the second exon in cold-treated larvae. Alternative promoter usage was detected for per3 gene under cold stress, which leading to a highly up-regulated transcript encoding a truncated protein lacking the C-terminal domains.ConclusionsThese findings indicate that zebrafish larvae possess the ability to build cold-tolerance under mild low temperature and transcriptional and post-transcriptional regulations are extensively involved in this acclimation process.
Highlights
Temperature is one of key environmental parameters that affect the whole life of fishes and an increasing number of studies have been directed towards understanding the mechanisms of cold acclimation in fish
This study aims to characterize the ability of zebrafish larvae to build cold-tolerance after exposed to a mild low temperature and investigate the transcriptional responses elicited by cold stress
Development of cold resistance in zebrafish larvae To address whether zebrafish larvae are able to build cold-resistance under a mild low temperature, 96 hpf larvae were incubated at 16°C for 24 h followed by severe cold exposure at 12°C and the controls were maintained at 28°C before severe cold exposure at 12°C (Figure 1A)
Summary
Temperature is one of key environmental parameters that affect the whole life of fishes and an increasing number of studies have been directed towards understanding the mechanisms of cold acclimation in fish. Researchers have characterized the transcriptional responses elicited by cold stress in fishes such as common carp (Cyprinus carpio) [15], zebrafish (Danio rerio) [16,17,18], channel catfish (Ictalurus punctatus) [19], annual killifish (Austrofundulus limnaeus) [20], coral reef fish (Pomacentrus moluccensis) [21] and rainbow trout (Oncorhynchus mykiss) [22] These investigations have revealed a large number of cold-regulated genes involved in a variety of biological processes that are associated with acclimation to both daily and seasonal low temperatures. The amplification cycle displaying the first significant increase of the fluorescence signal was defined as threshold cycle and used for quantification (Cq)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.