Mercury chloride exposure induces DNA damage, reduces fertility, and alters somatic and germline cells in Drosophila melanogaster ovaries
Mercury exposure has been shown to affect the reproductive system in many organisms, although the molecular mechanisms are still elusive. In the present study, we exposed Drosophila melanogaster Canton-S adult females to concentrations of 0 mM, 0.1 mM, 0.3 mM, 3 mM, and 30 mM of mercury chloride (HgCl2) for 24 h, 48 h, or 72 h to determine how mercury could affect fertility. Alkaline assays performed on dissected ovaries showed that mercury induced DNA damage that is not only dose-dependent but also time-dependent. All ovaries treated for 72 h have incorporated mercury and exhibit size reduction. Females treated with 30 mM HgCl2, the highest dose, had atrophied ovaries and exhibited a drastic 7-fold reduction in egg laying. Confocal microscopy analysis revealed that exposure to HgCl2 disrupts germinal and somatic cell organization in the germarium and leads to the aberrant expression of a germline-specific gene in somatic follicle cells in developing egg chambers. Together, these results highlight the potential long-term impact of mercury on germline and ovarian cells that might involve gene deregulation.
KeywordsDrosophila melanogaster DNA damage Gene regulation Fertility Germline Ovarian somatic cells Mercury chloride
We thank M. López-Carrasco, S. Gómez-Arroyo, J. Cortés-Eslava, A. R. Flores-Márquez, and the Centro de Ciencias de la Atmosfera, UNAM, for the infrastructural facilities. We are grateful to Jessica E. Treisman, Alain Vincent, Marc Amoyel, and Yannis E. Mavromatakis for their scientific feedback and to Dianne Heath for her careful proofreading of the manuscript. Imaging was acquired thanks to the UNICUA-LANSBIODyT project from CONACYT 280317 Facultad de Ciencias, UNAM.
This work was supported by resources provided by the CCA, UNAM, and CBD, Universite Paul Sabatier, Toulouse III. LHMV was supported by Mexican CONACYT.
Compliance with ethical standards
The authors declare that they have no competing interests.
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