Endocrine disruptors modulate expression of hepatic choriogenin genes in the hermaphroditic fish, Kryptolebias marmoratus.
Choriogenins (Chgs) are precursors of inner layer of egg envelope that are synthesized in fish liver in response to estrogens. Therefore, study of their expression serves as biomarker of exposure to endocrine disrupting chemicals (EDCs). The self-fertilizing fish, Kryptolebias marmoratus has been established as a model species for testing the action of EDCs. To use this fish as a model for assessing estrogenic activity of EDCs on Chg expression, two K. marmoratus choreogenin genes, Km-ChgH and Km-ChgL were cloned and their expression was analyzed in different tissues and in developmental stages by real-time RT-PCR. Expression levels of liver mRNA were compared between hermaphrodites and secondary males after exposure to EDCs. Km-ChgH and Km-ChgL genes that were predominantly expressed in liver contained zona pellucida (ZP) domains. During embryonic development, low expression of mRNA was observed at stage 1 (2 dpf) that reached highest level at stage 4 (12 dpf) or stage 5 (5 h post hatching). The expression of Km-Chg mRNAs was highly increased in liver exposed to natural estrogen, 17alpha-estradiol (E2) as well as EDCs such as bisphenol A and 4-n-nonylphenol in both the gender types. Another EDC, 4-tert-octylphenol, showed modulatory effect only on Km-ChgH in hermaphrodites. Tamoxifen, an antagonist of the estrogen receptor showed no effect on expression of Chg genes in either of the gender types of K. marmoratus. These findings indicate that Km-Chg genes would be associated with estrogen and measurement of their expression would serve as a surrogate biomarker of exposure to environmental EDCs.
Rhee
Jae-Sung
JS
Department of Molecular and Environmental Bioscience, Graduate School, Hanyang University, Seoul 133-791, South Korea.
Kang
Han Seung
HS
Raisuddin
Sheikh
S
Hwang
Dae-Sik
DS
Han
Jeonghoon
J
Kim
Ryeo-Ok
RO
Seo
Jung Soo
JS
Lee
Young-Mi
YM
Park
Gyung Soo
GS
Lee
Su-Jae
SJ
Lee
Jae-Seong
JS
D000818:Animals; D001559:Benzhydryl Compounds; D015415:Biomarkers / Q000378:metabolism; D003001:Cloning, Molecular; D004527:Egg Proteins / Q000235:genetics / Q000378:metabolism*; D052244:Endocrine Disruptors / Q000633:toxicity*; D004784:Environmental Monitoring / Q000379:methods; D004958:Estradiol / Q000633:toxicity; D004967:Estrogens / Q000633:toxicity*; D005260:Female; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D057850:Hermaphroditic Organisms; D007695:Killifishes / Q000196:embryology / Q000235:genetics / Q000378:metabolism*; D008099:Liver / Q000187:drug effects* / Q000196:embryology / Q000378:metabolism; D008297:Male; D010636:Phenols / Q000633:toxicity; D011498:Protein Precursors / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D019849:Sex Determination Processes; D013629:Tamoxifen / Q000633:toxicity; D013997:Time Factors; D000098826:Bisphenol A Compounds
D001559:Benzhydryl Compounds; D015415:Biomarkers; D004527:Egg Proteins; D052244:Endocrine Disruptors; D004958:Estradiol; D004967:Estrogens; D010636:Phenols; D011498:Protein Precursors; D012333:RNA, Messenger; D013629:Tamoxifen; C104950:choriogenin H; C041594:4-nonylphenol; C105260:4-tert-octylphenol; C006780:bisphenol A; D000098826:Bisphenol A Compounds