Ifremer, Laboratoire des Sciences de l'Environnement Marin (UMR 6539, LEMAR), Plouzané, France.
Biol Reprod. 2013 Oct 31;89(4):100. doi: 10.1095/biolreprod.113.109728. Print 2013 Oct.
The hermaphrodite Pacific oyster Crassostrea gigas displays a high energy allocation to reproduction. We studied the expression of AMP-activated protein kinase (AMPK) during gametogenesis in the gonad and characterized the mRNA sequences of the AMPK subunits: the AMPK alpha mRNA sequence was previously characterized; we identified AMPK beta, AMPK gamma, and mRNAs of putative AMPK-related targets following bioinformatics mining on existing genomic resources. We analyzed the mRNA expression of the AMPK alpha, beta, and gamma subunits in the gonads of male and female oysters through a reproductive cycle, and we quantified the mRNA expression of genes belonging to fatty acid and glucose metabolism. AMPK alpha mRNA levels were more abundant in males at the first stage of gametogenesis, when mitotic activity and the differentiation of germinal cells occur, and were always more abundant in males than in females. Some targets of fatty acid and glucose metabolism appeared to be correlated with the expression of AMPK subunits at the mRNA level. We then analyzed the sex-specific AMPK activity by measuring the phosphorylation of the catalytic AMPK alpha protein and its expression at the protein level. Both the amount of AMPK alpha protein and threonine 172 phosphorylation appeared to be almost totally inhibited in mature female gonads at stage 3, at the time when accumulation of reserves in oocytes was promoted, while it remained at a high level in mature spermatozoa. Its activation might play a sex-dependent role in the management of energy during gametogenesis in oyster.
雌雄同体的太平洋牡蛎（Crassostrea gigas）在繁殖过程中会大量分配能量。我们研究了性腺中 AMP 激活蛋白激酶（AMPK）在配子发生过程中的表达情况，并对 AMPK 亚基的 mRNA 序列进行了特征描述：之前已经对 AMPKαmRNA 序列进行了描述；通过对现有基因组资源进行生物信息学挖掘，我们鉴定了 AMPKβ、AMPKγ和推定的 AMPK 相关靶标 mRNA。我们通过生殖周期分析了雌雄牡蛎性腺中 AMPKα、β和γ亚基的 mRNA 表达，并定量了属于脂肪酸和葡萄糖代谢的基因的 mRNA 表达。在配子发生的第一阶段，当有丝分裂活动和生殖细胞分化发生时，雄性 AMPKαmRNA 水平更为丰富，而且雄性的 AMPKαmRNA 水平总是高于雌性。一些脂肪酸和葡萄糖代谢的靶标似乎与 AMPK 亚基的 mRNA 水平表达相关。然后，我们通过测量催化 AMPKα蛋白的磷酸化和其在蛋白水平上的表达来分析性别的特异性 AMPK 活性。在第三阶段，当卵母细胞中积累储备物时，成熟雌性性腺中 AMPKα蛋白的量及其丝氨酸 172 磷酸化似乎几乎完全受到抑制，而在成熟精子中则保持高水平。其激活可能在牡蛎配子发生过程中对能量的管理中发挥性别依赖性作用。
