BOA, INRA, Université de Tours, 37380, Nouzilly, France.
Institut Technique de l'Aviculture (ITAVI), Centre INRA Val de Loire, F-37380, Nouzilly, France.
BMC Genomics. 2019 Nov 7;20(1):821. doi: 10.1186/s12864-019-6185-0.
At sexual maturity, the liver of laying hens undergoes many metabolic changes to support vitellogenesis. In published transcriptomic approaches, hundreds of genes were reported to be overexpressed in laying hens and functional gene annotation using gene ontology tools have essentially revealed an enrichment in lipid and protein metabolisms. We reanalyzed some data from a previously published article comparing 38-week old versus 10-week old hens to give a more integrative view of the functions stimulated in the liver at sexual maturity and to move beyond current physiological knowledge. Functions were defined based on information available in Uniprot database and published literature.
Of the 516 genes previously shown to be overexpressed in the liver of laying hens, 475 were intracellular (1.23-50.72 fold changes), while only 36 were predicted to be secreted (1.35-66.93 fold changes) and 5 had no related information on their cellular location. Besides lipogenesis and protein metabolism, we demonstrated that the liver of laying hens overexpresses several clock genes (which supports the circadian control of liver metabolic functions) and was likely to be involved in a liver/brain/liver circuit (neurotransmitter transport), in thyroid and steroid hormones metabolisms. Many genes were associated with anatomical structure development, organ homeostasis but also regulation of blood pressure. As expected, several secreted proteins are incorporated in yolky follicles but we also evidenced that some proteins are likely participating in fertilization (ZP1, MFGE8, LINC00954, OVOCH1) and in thyroid hormone maturation (CPQ). We also proposed that secreted proteins (PHOSPHO1, FGF23, BMP7 but also vitamin-binding proteins) may contribute to the development of peripheral organs including the formation of medullar bones to provide labile calcium for eggshell formation. Thirteen genes are uniquely found in chicken/bird but not in human species, which strengthens that some of these genes may be specifically related to avian reproduction.
This study gives additional hypotheses on some molecular actors and mechanisms that are involved in basic physiological function of the liver at sexual maturity of hen. It also revealed some additional functions that accompany reproductive capacities of laying hens, and that are usually underestimated when using classical gene ontology approaches.
在性成熟时，母鸡的肝脏会经历许多代谢变化，以支持卵黄生成。在已发表的转录组学研究中，报道了数百个在母鸡中过度表达的基因，使用基因本体论工具进行的功能基因注释实质上揭示了脂质和蛋白质代谢的富集。我们重新分析了先前发表的一篇比较 38 周龄和 10 周龄母鸡的文章中的一些数据，以更全面地了解性成熟时肝脏中受刺激的功能，并超越当前的生理知识。功能是根据 Uniprot 数据库和已发表文献中的信息定义的。
在先前显示在母鸡肝脏中过度表达的 516 个基因中，有 475 个是细胞内基因（1.23-50.72 倍变化），而只有 36 个被预测为分泌蛋白（1.35-66.93 倍变化），还有 5 个没有关于其细胞位置的相关信息。除了脂肪生成和蛋白质代谢，我们还证明，母鸡的肝脏过度表达了几个时钟基因（支持肝脏代谢功能的昼夜节律控制），并且可能参与了肝脏/大脑/肝脏循环（神经递质转运）、甲状腺和类固醇激素代谢。许多基因与解剖结构发育、器官稳态以及血压调节有关。正如预期的那样，一些分泌蛋白被纳入蛋黄滤泡，但我们也证明了一些蛋白质可能参与受精（ZP1、MFGE8、LINC00954、OVOCH1）和甲状腺激素成熟（CPQ）。我们还提出，分泌蛋白（PHOSPHO1、FGF23、BMP7 以及维生素结合蛋白）可能有助于外围器官的发育，包括骨髓骨的形成，为蛋壳形成提供易变的钙。在鸡/鸟类中发现的 13 个基因在人类中没有发现，这进一步证明了其中一些基因可能与鸟类生殖有关。
本研究对一些分子因子和机制提供了额外的假设，这些因子和机制涉及母鸡性成熟时肝脏的基本生理功能。它还揭示了一些伴随母鸡繁殖能力的额外功能，而这些功能在使用经典基因本体论方法时通常被低估。
