Zebrafish (Danio rerio) life-cycle exposure to chronic low doses of ethinylestradiol modulates p53 gene transcription within the gonads, but not NER pathways
- Authors
- Soares, J., Castro, L.F., Reis-Henriques, M.A., Monteiro, N.M., and Santos, M.M.
- ID
- ZDB-PUB-120503-8
- Date
- 2012
- Source
- Ecotoxicology (London, England) 21(5): 1513-1522 (Journal)
- Registered Authors
- Santos, Manuel
- Keywords
- zebrafish, ethinylestradiol, pharmacuetical, embryonic development, p53, NER, aneuploidy, environmental risk assessment
- MeSH Terms
-
- Animals
- Cyclin-Dependent Kinases/genetics
- Cyclin-Dependent Kinases/metabolism
- DNA/genetics
- DNA/metabolism
- DNA Damage/drug effects
- DNA Repair/drug effects*
- Embryo, Nonmammalian/drug effects
- Embryo, Nonmammalian/metabolism
- Environmental Exposure/adverse effects*
- Environmental Exposure/analysis
- Ethinyl Estradiol/toxicity*
- Female
- Gonads/drug effects
- Gonads/growth & development
- Life Cycle Stages/drug effects
- Male
- Real-Time Polymerase Chain Reaction
- Toxicity Tests, Chronic/methods
- Transcription, Genetic
- Tumor Suppressor Protein p53/genetics*
- Tumor Suppressor Protein p53/metabolism
- Water Pollutants, Chemical/analysis
- Water Pollutants, Chemical/toxicity
- Zebrafish/genetics*
- Zebrafish/growth & development
- bcl-2-Associated X Protein/genetics
- bcl-2-Associated X Protein/metabolism
- PubMed
- 22543959 Full text @ Ecotoxicology
Parental full life-cycle exposure to ethinylestradiol (EE2) significantly affects embryo development and survival. One of the possible mechanisms of action of EE2 may involve the impairment of an organism’s ability to repair DNA damage. DNA repair mechanisms have sophistically evolved to overcome DNA damaging hazards that threaten the integrity of the genome. In the present study, changes in the transcription levels of key genes involved in two of the most thoroughly studied DNA repair systems in mammals were evaluated in adult zebrafish (Danio rerio) gonad upon full life-cycle exposure to chronic environmentally low levels of EE2 (i.e., 0.5, 1 and 2 ng/L EE2). Real time PCR was used to analyse the expression levels of nucleotide excision repair genes (NER) as well as the tumor suppressor p53 and downstream selected effectors, i.e., p21 (cyclin-dependent kinase inhibitor), GADD45α (growth arrest and DNA damage induced 45, alpha), bax (bcl2-associated X protein) and p53 key regulator MDM2 (murine double minute 2 protein). NER genes transcription levels in gonads did not differ significantly among treatments. In contrast, the number of transcripts of p53 gene was significantly increased in male gonads at all EE2 exposure concentrations and in females at 1 ng/L EE2. Despite the increase in p53 transcripts, transcription levels of p21, GADD45α and bax genes were not affected upon EE2 treatment, whereas MDM2 gene expression significantly increased in females at the intermediate EE2 dose (1 ng/L). Overall, the present study indicate that chronic low levels of EE2 significantly modulates the transcription of p53, a key gene involved in DNA repair, particularly in male zebrafish gonads, which supports the hypothesis of an impact of EE2 in male gonad DNA repair pathways.