ABSTRACT
Embryos of marine organisms whose development occurs externally are particularly sensitive to ultraviolet (UV) light (bands A and B, respectively, UVA and UVB). ATP-binding cassette (ABC) transporters are the first line of cellular defense against chemical or physical stress. The present work investigated the involvement of ABC transporters on UVA or UVB effects on eggs, spermatozoa, and embryonic cells of the sea urchin Echinometra lucunter. Gametes or embryos were exposed to UVA (3.6-14.4 kJ m(-2)) or UVB (0.112-14.4 kJ m(-2)), and embryonic development was monitored by optical microscopy at different developmental stages in the presence or absence of the ABC-transporter blockers reversin205 (ABCB1 blocker) or MK571 (ABCC1 blocker). E. lucunter eggs, spermatozoa and embryos were resistant to UVA exposure. Resistance to the harmful effects of UVB was strongly associated to ABC transporter activity (embryos > eggs > spermatozoa). ABCB1 or ABCC1 blockage promoted the injurious effects of UVA on spermatozoa. ABCC1 transporter blockage increased UVB-dependent damage in eggs while ABCB1 transporter inhibition increased harmful effects of UVB in embryonic cells. ABC-transporter activity was not, however, affected by UVB exposure. In conclusion, the present study is the first report on the protective role of ABC transporters against harmful effects of UVA and UVB on sea urchin eggs and embryonic cells.
