P. lividus oogenesis and early development require autophagy

Abstract

It is well known that autophagy is a major intracellular pathway for the degradation and recycling of cytosolic components, in both basal and stress conditions. We have recently demonstrated the activation of autophagy in P. lividus embryos: at high levels, after a stress induced by cadmium, and at basal levels, during the physiological development (1) (2). Here we report ours recent data about autophagy during oogenesis and segmentation. In order to detect autophagolysosomes (AVOs) and autolysosomes, we respectively performed incubation in vivo with acridine orange (AO), and in situ immunofluorescence (IF) with the anti-LC3 antibody (autophagy marker). All observations were carried out by Confocal Laser Scanning Microscopy. In this way we studied the trend of autophagy during oocytes maturation, after fertilization and during early developmental stages and results showed that, in all cases, the autophagic markers have specific and peculiar localizations. Furthermore we observed that the treatment with bafilomycin A1 (an inhibitor of autophagy) for 2 hours, after fertilization, generates developmental delays and morphologic anomalies, especially visible after 24 hours of development, demonstrating that autophagy is essential during the early developmental stages. This data showed the occurrence of autophagy in oocytes and during segmentation, in the first case probably for the recycling of cellular components that accumulate during oogenesis and for the elimination of the germinal vesicle, in the second case, perhaps for the removal of cellular components, between one cleavage and the following. (1) CHIARELLI R. et al. (2011) Sea urchin embryos as a model system for studying autophagy induced by cadmium stress. Autophagy. 7(9): 1028-34. (2) KLIONSKY D. et al. (2012) Guidelines for the use and interpretation of assays for monitoring autophagy (Review). Autophagy. 8(4): 1–100.