Thyroid hormone coordinates developmental trajectories but does not underlie developmental truncation in danionins
Thyroid hormone coordinates developmental trajectories but does not underlie developmental truncation in danionins
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DOI：
10.1002/dvdy.76
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发表时间：
2019-07-02
影响因子：
2.5
通讯作者：
McMenamin, Sarah
中科院分区：
文献类型：
--
作者：
Hu, Yinan;Mauri, Angela;McMenamin, Sarah
背景胚后发育轨迹的差异可以深刻地改变成人的表型和生活史。甲状腺激素（TH）调节变态在许多脊椎动物类群与多相生态，TH代谢的改变是显着的情况下，在两栖动物的paedomorphosis。我们测试的要求TH在多个胚后发育过程中的斑马鱼，这具有一个双相生态，并询问TH生产是否受到损害的幼态Danionella。结果TH对斑马鱼幼鱼的异速生长有调节作用，并抑制头部的相对生长。侧线系统表现出不同的要求TH：激素促进管神经肥大的形成和抑制神经肥大增殖的头部，但会导致扩大的神经肥大人口的躯干。虽然Danionella形态类似于斑马鱼幼体，但分析的两种Danionella物种在其形状或神经肥大分布方面与甲状腺功能减退的斑马鱼不相似，并且都具有功能性甲状腺滤泡。结论虽然斑马鱼不经历离散的生态转变，我们发现，多个组织经历的发展轨迹，是依赖于TH的过渡，这表明TH轴及其下游途径作为适应的可能目标。然而，我们没有发现证据表明Danionella的进化Paedomorphosis是TH生产受损的结果。
Background Differences in postembryonic developmental trajectories can profoundly alter adult phenotypes and life histories. Thyroid hormone (TH) regulates metamorphosis in many vertebrate taxa with multiphasic ecologies, and alterations to TH metabolism underlie notable cases of paedomorphosis in amphibians. We tested the requirement for TH in multiple postembryonic developmental processes in zebrafish, which has a monophasic ecology, and asked if TH production was compromised in paedomorphic Danionella. Results We showed that TH regulates allometric growth in juvenile zebrafish, and inhibits relative head growth. The lateral line system showed differential requirements for TH: the hormone promotes canal neuromast formation and inhibits neuromast proliferation in the head, but causes expansion of the neuromast population in the trunk. While Danionella morphology resembled that of larval zebrafish, the two Danionella species analyzed were not similar to hypothyroid zebrafish in their shape or neuromast distribution, and both possessed functional thyroid follicles. Conclusions Although zebrafish do not undergo a discrete ecological transformation, we found that multiple tissues undergo transitions in developmental trajectories that are dependent on TH, suggesting the TH axis and its downstream pathways as likely targets for adaptation. Nonetheless, we found no evidence that evolutionary paedomorphosis in Danionella is the result of compromised TH production.