Altered gonadal expression of TGF-β superfamily signaling factors in environmental contaminant-exposed juvenile alligators.
Environmental contaminant exposure can influence gonadal steroid signaling milieus; however, little research has investigated the vulnerability of non-steroidal signaling pathways in the gonads. Here we use American alligators (Alligator mississippiensis) hatched from field-collected eggs to analyze gonadal mRNA transcript levels of the activin-inhibin-follistatin gene expression network and growth differentiation factor 9. The eggs were collected from Lake Woodruff National Wildlife Refuge, a site with minimal anthropogenic influence, and Lake Apopka, a highly contaminated lake adjacent to a former EPA Superfund site. The hatchling alligators were raised for 13 months under controlled conditions, thus limiting differences to embryonic origins. Our data reveal sexually dimorphic mRNA expression in 13-month-old alligator gonads similar to patterns established in vertebrates with genetic sex determination. In addition, we observed a relationship between lake of origin and mRNA expression of activin/inhibin subunits α and βB, follistatin, and growth differentiation factor 9. Our study suggests that embryonic exposure to environmental contaminants can affect future non-steroidal signaling patterns in the gonads of a long-lived species.
Department of Biology, University of Florida, Gainesville, FL 32611-8525, USA. bmoore2@tulane.edu
Brandon C
BC
Moore
Matthew R
MR
Milnes
Satomi
S
Kohno
Yoshinao
Y
Katsu
Taisen
T
Iguchi
Teresa K
TK
Woodruff
Louis J
LJ
Guillette
D028341:Activins / Q000096:biosynthesis; D000489:Alligators and Crocodiles / Q000378:metabolism*; D000818:Animals; D052244:Endocrine Disruptors / Q000633:toxicity*; D004781:Environmental Exposure; D004785:Environmental Pollutants / Q000633:toxicity*; D005260:Female; D038681:Follistatin / Q000096:biosynthesis; D006066:Gonads / Q000187:drug effects* / Q000378:metabolism; D055429:Growth Differentiation Factor 9 / Q000096:biosynthesis; D007265:Inhibins / Q000378:metabolism; D008297:Male; D010063:Ovum; D019849:Sex Determination Processes / Q000187:drug effects; D015398:Signal Transduction; D016212:Transforming Growth Factor beta / Q000378:metabolism*
D052244:Endocrine Disruptors; D004785:Environmental Pollutants; D038681:Follistatin; D055429:Growth Differentiation Factor 9; D016212:Transforming Growth Factor beta; D028341:Activins; D007265:Inhibins