Back to Search
Start Over
CRISPR-Cas9-Mutated Pregnane X Receptor (pxr) Retains Pregnenolone-induced Expression of cyp3a65 in Zebrafish (Danio rerio) Larvae
- Source :
- Toxicol Sci
- Publication Year :
- 2019
- Publisher :
- Oxford University Press (OUP), 2019.
-
Abstract
- Pregnane X receptor (PXR; NR1I2) is a nuclear receptor that regulates transcriptional responses to drug or xenobiotic exposure, including induction of CYP3A transcription, in many vertebrate species. PXR is activated by a wide range of ligands that differ across species, making functional studies on its role in the chemical defensome most relevant when approached in a species-specific manner. Knockout studies in mammals have shown a requirement for PXR in ligand-dependent activation of CYP3A expression or reporter gene activity. Morpholino knockdown of Pxr in zebrafish indicated a similar requirement. Here, we report on the generation of 2 zebrafish lines each carrying a heritable deletion in the pxr coding region, predicted to result in loss of a functional gene product. To our surprise, larvae homozygous for either of the pxr mutant alleles retain their ability to induce cyp3a65 mRNA expression following exposure to the established zebrafish Pxr ligand, pregnenolone. Thus, zebrafish carrying pxr alleles with deletions in either the DNA binding or the ligand-binding domains did not yield a loss-of-function phenotype, suggesting that a compensatory mechanism is responsible for cyp3a65 induction. Alternative possibilities are that Pxr is not required for the induction of selected genes, or that truncated yet functional mutant Pxr is sufficient for the downstream transcriptional effects. It is crucial that we develop a better understanding for the role of Pxr in this important biomedical test species. This study highlights the potential for compensatory mechanisms to avoid deleterious effects arising from gene mutations.
- Subjects :
- 0301 basic medicine
Mutant
Gene mutation
Biology
Ligands
Toxicology
digestive system
Animals, Genetically Modified
03 medical and health sciences
0302 clinical medicine
Transcription (biology)
Emerging Technologies, Methods, and Models
Animals
Gene
Zebrafish
Cytochrome P-450 Enzyme Inducers
Pregnane X receptor
Reporter gene
Pregnane X Receptor
Oxidoreductases, N-Demethylating
Zebrafish Proteins
biology.organism_classification
digestive system diseases
Cell biology
030104 developmental biology
Nuclear receptor
Enzyme Induction
Pregnenolone
Gene Targeting
Mutation
Aryl Hydrocarbon Hydroxylases
CRISPR-Cas Systems
030217 neurology & neurosurgery
Subjects
Details
- ISSN :
- 10960929 and 10966080
- Volume :
- 174
- Database :
- OpenAIRE
- Journal :
- Toxicological Sciences
- Accession number :
- edsair.doi.dedup.....34b903690a6d9aecc2524c866d04fc4b