Department of Fish Physiology and Biotechnology, Instituto de Acuicultura de Torre la Sal, Consejo Superior de Investigaciones Científicas (CSIC), 12595 Torre la Sal, Ribera de Cabanes s/n, Castellón, Spain.
Gen Comp Endocrinol. 2013 Dec 1;194:81-93. doi: 10.1016/j.ygcen.2013.08.016. Epub 2013 Sep 14.
FOXL2 is a forkhead transcription factor involved in mammalian development and regulation of reproduction. Two foxl2 paralogs, foxl2a and foxl2b, have been described in various teleost species and were considered as fish-specific duplicates. Here, we report the isolation and characterization of foxl2a (foxl2) and foxl2b (foxl3) in European sea bass (Dicentrarchus labrax), together with the identification of these two genes in non-teleost genomes. Phylogenetic and synteny analyses indicate that these paralogs originated from an ancient genome duplication event that happened long before the teleost specific duplication. While foxl2/foxl2a has been maintained in most vertebrate lineages, foxl2b, which we propose to rename as foxl3, was repeatedly lost in tetrapods. Gonadal expression patterns of the sea bass genes point to a strong sexual dimorphism, and the mRNA levels of foxl2 in ovary and foxl3 in testis vary significantly during the reproductive cycle. When overexpressed in cultured ovarian follicular cells, foxl2 and foxl3 produced functional transcription factors able to control the expression of reproduction-related genes. Taken together, these data suggest that Foxl2 may play a conserved role in ovarian maturation, while Foxl3 could be involved in testis physiology.
FOXL2 是一种参与哺乳动物发育和生殖调控的叉头转录因子。两种 foxl2 旁系同源物，foxl2a 和 foxl2b，已在各种硬骨鱼物种中被描述，并被认为是鱼类特有的重复基因。在这里，我们报告了欧洲鲈鱼（Dicentrarchus labrax）中 foxl2a（foxl2）和 foxl2b（foxl3）的分离和特征，以及这些基因在非硬骨鱼基因组中的鉴定。系统发育和基因同线性分析表明，这些旁系同源物起源于一个古老的基因组复制事件，该事件发生在硬骨鱼特异性复制之前很久。虽然 foxl2/foxl2a 已在大多数脊椎动物谱系中得到保留，但 foxl2b，我们提议将其重新命名为 foxl3，在四足动物中被多次丢失。鲈鱼基因的性腺表达模式显示出强烈的性别二态性，并且 foxl2 在卵巢和 foxl3 在睾丸中的 mRNA 水平在生殖周期中差异显著。当在培养的卵巢滤泡细胞中过表达时，foxl2 和 foxl3 产生功能性转录因子，能够控制与生殖相关基因的表达。综上所述，这些数据表明 Foxl2 可能在卵巢成熟中发挥保守作用，而 Foxl3 可能参与睾丸生理学。
