Abstract：
Autophagy is essential for oocyte maturation and preimplantation embryo development. ATG4C, a member of the ATG4 family, plays a crucial role in the autophagy process. The effect of ATG4C on the early embryonic development in pig has not been studied. In this study, the expression patterns of ATG4C were explored using qRT-PCR and immunofluorescence staining. Different concentrations of serum were added to in vitro maturation (IVM) medium to investigate its effects on oocyte maturation and embryonic development. Finally, the developmental potential of parthenogenetic embryos was detected by downregulating ATG4C in MII stage oocytes under 0 % serum condition. The results revealed that ATG4C was highly expressed in porcine oocytes matured in vitro and in parthenogenetic embryos. Compared with the 10 % serum group, the cumulus cell expansion, first polar body (PB1) extrusion rate, and subsequent developmental competence of embryos were reduced in the 0 % and 5 % serum groups. The mRNA levels of LC3, ATG5, BECLIN1, TFAM, PGC1α, and PINK1 were significantly increased (P < 0.05) in the 0 % serum group. ATG4C was significantly upregulated in the embryos at the 1-cell, 2-cell, 8-cell, and 16-cell stages in the 0 % serum group (P < 0.05). Compared with the negative control group, downregulation of ATG4C significantly decreased the 4-cell, 8-cell, and blastocyst rates (P < 0.05), and the expression of genes related to autophagy, mitochondria, and zygotic genome activation (ZGA) was significantly decreased (P < 0.05). The relative fluorescence intensity of LC3 and mitochondrial content in the ATG4C siRNA group was significantly reduced (P < 0.05). Collectively, the results indicate that ATG4C is highly expressed in porcine oocytes matured in vitro and in early embryos, and inhibition of ATG4C effects embryonic developmental competence by decreasing autophagy, mitochondrial content, and ZGA under serum-free condition.
摘要：
自噬对卵母细胞成熟和植入前胚胎发育至关重要。ATG4C,ATG4家族的一员,在自噬过程中起着至关重要的作用。ATG4C对猪早期胚胎发育的影响尚未研究。在这项研究中,使用qRT-PCR和免疫荧光染色探索ATG4C的表达模式。将不同浓度的血清添加到体外成熟（IVM）培养基中，以研究其对卵母细胞成熟和胚胎发育的影响。最后,在0％血清条件下，通过下调MII期卵母细胞中的ATG4C来检测孤雌生殖胚胎的发育潜力。结果表明，ATG4C在体外成熟的猪卵母细胞和孤雌生殖胚胎中高表达。与10%血清组相比，卵丘细胞扩张，第一极体（PB1）挤出率，在0％和5％血清组中，胚胎的发育能力降低。LC3、ATG5、BECLIN1、TFAM、PGC1α,0%血清组PINK1明显增高(P<0.05)。ATG4C在1细胞的胚胎中显著上调，2细胞，8细胞，0%血清组16细胞分期(P<0.05)。与阴性对照组相比,ATG4C的下调显著降低了4细胞，8细胞，囊胚率（P<0.05），以及自噬相关基因的表达，线粒体,合子基因组激活(ZGA)显著降低(P<0.05)。ATG4CsiRNA组LC3的相对荧光强度和线粒体含量显著降低(P<0.05)。总的来说，结果表明，ATG4C在体外成熟的猪卵母细胞和早期胚胎中高表达，抑制ATG4C通过减少自噬影响胚胎发育能力，线粒体含量，和ZGA在无血清条件下。
