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Series GSE11893 Query DataSets for GSE11893
Status Public on Nov 01, 2008
Title AHR Activation by TCDD Downregulates Sox9b Expression Producing Jaw Malformation in Zebrafish Embryos
Organism Danio rerio
Experiment type Expression profiling by array
Summary Exposure to environmental contaminants can disrupt normal development of the early vertebrate skeleton. 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) impairs craniofacial skeletal development across many vertebrate species and its effects are especially prominent in early life stages of fish. TCDD activates the aryl hydrocarbon receptor (AHR), a transcription factor that mediates most if not all TCDD responses. We investigated the transcriptional response in the developing zebrafish jaw following TCDD exposure using DNA microarrays. Zebrafish larvae were exposed to TCDD at 96 h postfertilization (hpf) and jaw cartilage tissue was harvested for microarray analysis at 1, 2, 4 and 12 h postexposure (hpe). Numerous chondrogenic transcripts were misregulated by TCDD in the jaw. Comparison of transcripts altered by TCDD in jaw with transcripts altered in embryonic heart showed that the transcriptional responses in the jaw and the heart were strikingly different. Sox9b, a critical chondrogenic transcription factor, was the most significantly reduced transcript in the jaw. We hypothesized that the TCDD reduction of sox9b expression plays an integral role in affecting formation of the embryonic jaw. Morpholino knock down of sox9b expression demonstrated that partial reduction of sox9b expression alone was sufficient to produce a TCDD-like jaw phenotype. Heterozygous sox9b deletion mutant embryos were sensitized to TCDD. Lastly, embryos injected with sox9b mRNA and then exposed to TCDD blocked TCDD-induced jaw toxicity in approximately 14% of sox9b-injected embryos. These results suggest that reduced sox9b expression in TCDD-exposed zebrafish embryos contributes to jaw malformation.

Keywords: Time course
Overall design Three independent replicate microarray time course experiments were performed comparing transcript levels between TCDD-exposed and control zebrafish. For each experiment, zebrafish were exposed to TCDD for 1 h starting at 96 hpf as described above. For each time point (97, 98, 100 and 108 hpf) and treatment jaw samples were pooled from 10 dissections for RNA isolation and hybridization with Affymetrix zebrafish arrays (Affymetrix, Santa Clara, CA). Each microarray contains roughly 14,900 probes corresponding to approximately 30% of the zebrafish genome. For each array, total RNA (1 µg) was isolated from 10 jaw microdissections with the QIAGEN RNeasy Mini kit following the manufacturer’s protocol (QIAGEN, Valencia, CA). The One-Cycle Target Labeling and Control Reagents kit was used to synthesize cDNA and biotinylated cRNA following the manufacturer’s protocol (Affymetrix, Santa Clara, CA). Biotin-labeled cRNA (15 µg) was fragmented and hybridized onto Affymetrix Zebrafish Genechip Arrays following the protocol in the Affymetrix Genechip Expression Analysis Technical Manual. Following hybdrization, the arrays were washed and stained with streptavidin-phycoerythrin on an Affymetrix Fluidics Station 400 using the protocol EukGE WS2v4. Arrays were scanned with an Agilent Gene Array Scanner.
Contributor(s) Xiong KM, Peterson RE, Heideman W
Citation(s) 18784347
Submission date Jun 26, 2008
Last update date Jan 25, 2018
Contact name Kong M Xiong
Organization name University of Wisconsin at Madison
Department Biomolecular Chemistry
Lab Heideman/Peterson Fish Group
Street address 777 Highland Ave, 5208 Rennebohm Hall
City Madison
State/province WI
ZIP/Postal code 53705
Country USA
Platforms (1)
GPL1319 [Zebrafish] Affymetrix Zebrafish Genome Array
Samples (24)
GSM300495 jaw_vehicle control_1h_rep1
GSM300496 jaw_vehicle control_1h_rep2
GSM300497 jaw_vehicle control_1h_rep3
BioProject PRJNA105721

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Supplementary file Size Download File type/resource
GSE11893_RAW.tar 77.9 Mb (http)(custom) TAR (of CEL)
Raw data provided as supplementary file
Processed data included within Sample table

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