PUBLICATION

Use of gene knockout to examine serotonergic control of ion uptake in zebrafish reveals the importance of controlling for genetic background: A cautionary tale

Authors
Zimmer, A.M., Do, J., Szederkenyi, K., Chen, A., Morgan, A.L.R., Jensen, G., Pan, Y.K., Gilmour, K.M., Perry, S.F.
ID
ZDB-PUB-190826-25
Date
2019
Source
Comparative biochemistry and physiology. Part A, Molecular & integrative physiology   238: 110558 (Journal)
Registered Authors
Perry, Steve F.
Keywords
CRISPR/Cas9, Calcium (Ca(2+)) uptake, Danio rerio, Ion regulation, Serotonin (5-HT), Sodium (Na(+)) uptake, Strain
MeSH Terms
  • Animals
  • Calcium/metabolism
  • Fertilization
  • Gene Knockout Techniques*
  • Ions
  • Serotonin/metabolism*
  • Sodium/metabolism
  • Zebrafish/genetics*
  • Zebrafish/metabolism*
  • Zebrafish Proteins/metabolism
PubMed
31446068 Full text @ Comp. Biochem. Physiol. A Mol. Integr. Physiol.
Abstract
Freshwater (FW) fishes inhabit dilute environments and must actively absorb ions in order to counteract diffusive salt loss. Neuroendocrine control of ion uptake in FW fishes is an important feature of ion homeostasis and several important neuroendocrine factors have been identified. The role of serotonin (5-HT), however, has received less attention despite several studies poiting to a role for 5-HT in the control of ion balance. Here, we used a gene knockout approach to elucidate the role of 5-HT in regulating Na+ and Ca2+ uptake rates in larval zebrafish. Tryptophan hydroxylase (TPH) is the rate-limiting step in 5-HT synthesis and we therefore hypothesized that ion uptake rates would be altered in zebrafish larvae carrying knockout mutations in tph genes. We first examined the effect of tph1b knockout (KO) and found that tph1bKO larvae, obtained from Harvard University, had reduced rates of Na+ and Ca2+ uptake compared to wild-type (WT) larvae from our institution (uOttawa WT), lending support to our hypothesis. However, further experiments controlling for differences in genetic background demonstrated that WT larvae from Harvard University (Harvard WT) had lower ion uptake rates than those of uOttawa WT, and that ion uptake rate between Harvard WT and tph1bKO larvae were not significantly different. Therefore, our initial observation that tph1bKO larvae (Harvard source) had reduced ion uptake rates relative to uOttawa WT was a function of genetic background and not of knockout itself. These data provide a cautionary tale of the importance of controlling for genetic background in gene knockout experiments.
Genes / Markers
Figures
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Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Antibodies
Orthology
Engineered Foreign Genes
Mapping