Abstract. Autophagy, an essential process for cellular maintenance, cell viability, and development, is the bulk degradation of proteins and organelles. This study investigated the expression levels of autophagy-related genes and the effect of 3-methyladenine (3-MA, an autophagy inhibitor) or rapamycin (an autophagy inducer) on maternal gene degradation and apoptosis in porcine parthenotes developing in vitro. LC3, which is essential for the formation of autophagosomes, was widely expressed in porcine parthenotes. High levels of autophagy-related genes, Atg5, Beclin1 and Lc3 transcripts were expressed in the 1-cell (1C) stage and gradually decreased through the 2-cell (2C) to blastocyst stages. The mRNA expression of Gdf9, c-mos and cyclin B maintained high levels in 2C and 4-cell (4C) embryos treated with 3-MA compared with the control. The Bmp15 and cyclin B mRNA levels were significantly reduced in embryos treated with rapamycin compared with the control. These results suggest that autophagy influences the degradation of these maternal genes. Furthermore, 3-MA-treated embryos exhibited significantly reduced developmental rates, decreased total cell numbers and increased rates of apoptosis. Expression of Atg5, Beclin1 and Lc3 and synthesis of LC3 protein were significantly reduced at the blastocyst stage. Although rapamycin treatment did not affect the developmental rate, it decreased the cell number and increased the rate of apoptosis, and the expression of Atg5, Beclin1 and Lc3 and LC3 protein synthesis were increased. Finally, blastocysts derived following treatment with 3-MA or rapamycin exhibited significantly decreased expression of selected transcription factors, including Pou5f1, Sox2 and Nanog. In conclusion, our results demonstrate that autophagy influences maternal mRNA degradation and apoptosis at the blastocyst stage and suggest that autophagy plays an important role in early embryo development in the pig. Key words: Apoptosis, Autophagy, LC3, Maternal gene, 3-MA, Rapamycin (J. Reprod. Dev. 58: [576][577][578][579][580][581][582][583][584] 2012) A utophagy is an intracellular, bulk degradation process in which a portion of the cytoplasm is sequestered in an autophagosome and subsequently degraded upon fusion with a lysosome [1][2][3]. Autophagy plays a critical role during fertilization [4] and an essential role in differentiation and development, as well as in the cellular response to stress. Our previous study was the first to report that mitochondrial stress influences autophagy in porcine parthenotes developing in vitro [5]. However, the role of autophagy in early porcine parthenotes is still poorly understood.A balance between the formation and degradation of cellular proteins is required for cell survival. In mammals, protein degradation is accelerated shortly after fertilization and is apparent by the early two-cell stage in mice [6] and the four-cell stage in pigs. Early embryogenesis may rely on maternal protein stores as nutrients. After fertilization, maternal proteins in oocytes are...