title: Imposex development in Hexaplex trunculus (Gastropoda: Caenogastropoda) involves changes in the transcription levels of the retinoid X receptor (RXR).
abstract: In order to further demonstrate that TBT-induced imposex through RXR signaling is not species-specific, Hexaplex trunculus was selected as an experimental model species. We first isolated RXR in H. trunculus, and determined gene transcription through quantitative real-time PCR in key tissues (e.g., penis/penis-forming area and central nervous system:- CNS), upon exposure to tributyltin (TBT) (5 and 50 ng TBTL(-1)). Two months of exposure to TBT induced imposex and led to a significant increase in the severity of the phenomenon in females and an increase in male penis lengths. Exposure to TBT altered RXR gene transcription in a tissue and sex-specific manner. In the CNS, there were no significant changes in RXR gene transcription between control and TBT-exposed females. A similar trend was observed in male CNS. On the contrary, in the penis-forming area/penis of females exposed to TBT, a significant increase in RXR gene transcription was observed in the 50 ng TBTL(-1) group. Furthermore, a positive correlation was observed between overall female penis lengths and RXR gene transcription. In males, although a trend towards an increase in RXR gene transcription in penis was observed, differences did not reach significance. Overall, the results of the present study give further support to a local role of RXR in the penis-forming area during the development of imposex by TBT, thus suggesting a conserved function of RXR in penis formation at least within prosobranch gastropods.
authors.affiliation: Laboratory of Environment Biomonitoring, University of Carthage, Faculty of Sciences of Bizerta (FSB), 7021 Zarzouna, Bizerta, Tunisia. Electronic address: abidli_sami@yahoo.fr.
authors.forename: Sami
authors.initials: S
authors.lastname: Abidli
authors.forename: Luis Filipe Costa
authors.initials: LF
authors.lastname: Castro
authors.forename: Youssef
authors.initials: Y
authors.lastname: Lahbib
authors.forename: Maria Armanda
authors.initials: MA
authors.lastname: Reis-Henriques
authors.forename: Najoua
authors.initials: N
authors.lastname: Trigui El Menif
authors.forename: Miguel Machado
authors.initials: MM
authors.lastname: Santos
mesh_terms: D000818:Animals; D002490:Central Nervous System; D012734:Disorders of Sex Development / Q000139:chemically induced / Q000378:metabolism / Q000662:veterinary*; D005260:Female; D049851:Gastropoda / Q000502:physiology*; D015870:Gene Expression / Q000187:drug effects; D008297:Male; D047488:Retinoid X Receptors / Q000235:genetics* / Q000378:metabolism; D014220:Trialkyltin Compounds / Q000633:toxicity; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D047488:Retinoid X Receptors; D014220:Trialkyltin Compounds; D014874:Water Pollutants, Chemical; C011559:tributyltin
keywords: Gene expression; Hexaplex trunculus; Imposex; RXR; TBT