Transcriptional profiling of the parr–smolt transformation in Atlantic salmon

Abstract

The parr-smolt transformation in Atlantic salmon (Salmo salar) is a complex developmental process that culminates in the ability to migrate to and live in seawater. We used GRASP 16K cDNA microarrays to identify genes that are differentially expressed in the liver, gill, hypothalamus, pituitary, and olfactory rosettes of smolts compared to parr. Smolts had higher levels of gill Na + /K + -ATPase activity, plasma cortisol and plasma thyroid hormones relative to parr. Across all five tissues, stringent microarray analyses identified 48 features that were differentially expressed in smolts compared to parr. Using a less stringent method we found 477 features that were differentially expressed at least 1.2-fold in smolts, including 172 features in the gill. Smolts had higher mRNA levels of genes involved in transcription, protein biosynthesis and folding, electron transport, oxygen transport, and sensory perception and lower mRNA levels for genes involved in proteolysis. Quantitative RT-PCR was used to confirm differential expression in select genes identified by microarray analyses and to quantify expression of other genes known to be involved in smolting. This study expands our understanding of the molecular processes that underlie smolting in Atlantic salmon and identifies genes for further investigation.Published by Elsevier Inc.

An integrated transcriptomic and comparative genomic analysis of differential gene expression in Arctic charr (Salvelinus alpinus) following seawater exposure

“…Only nine genes in sockeye salmon (Evans et al, 2011) and seven genes in Atlantic salmon (Seear et al, 2010;Robertson and McCormick, 2012) showed patterns of DE that were consistent with our observations (Table 6). It must be emphasized that differences in experimental design and in the technical platforms used by others (Seear et al, 2010;Evans et al, 2011;Robertson and McCormick, 2012) may account for these differences.…”

“…We compared the results of this study with similar research on Atlantic salmon (Seear et al, 2010;Robertson and McCormick, 2012) and sockeye salmon (Evans et al, 2011). Only nine genes in sockeye salmon (Evans et al, 2011) and seven genes in Atlantic salmon (Seear et al, 2010;Robertson and McCormick, 2012) showed patterns of DE that were consistent with our observations (Table 6).…”

“…Finally, we provided evidence that interchromosomal rearrangements have played a role in the evolution of hypo-osmoregulation in Arctic charr. Up-regulated genes denoted by '+'; down-regulated genes denoted by '-'; data for Arctic charr (AC) are from this study; data for sockeye salmon (SS) were obtained from Evans et al (Evans et al, 2011), and for Atlantic salmon (AS) from Seear et al (Seear et al, 2010) and Robertson and McCormick (Robertson and McCormick, 2012); genes assigned +/− consist of independent contigs that align to the same reference sequence but exhibit divergent expression profiles.…”

Ontogenetic changes in embryonic and brain gene expression in progeny produced from migratory and resident Oncorhynchus mykiss

“…; Nolte et al . ; Robertson & McCormick ; Sutherland et al . ) and gene network analysis (Filteau et al .…”

Variation in branchial expression among insulin-like growth-factor binding proteins (igfbps) during Atlantic salmon smoltification and seawater exposure

“…The progressive increase in the salt secretory capacity of the gill during smoltification entails developmentally cued patterns of ionocyte differentiation and proliferation, in addition to altered gene transcription within these ionocytes [8, 42, 43]. Knowing that the Gh/Igf axis directs the timing and nature of these cellular behaviors [13–15], we hypothesized that Igfbps contribute to smoltification and therefore would exhibit seasonal and SW-responsive patterns of gene expression.…”