Structure and function of brain and nerve cord-endocrine system in amphioxus

文昌鱼脑及神经索内分泌系统的结构与功能

基本信息

批准号：
15570046
负责人：
KUBOKAWA Kaoru
金额：
$ 1.73万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2004
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15570046/
关键词：
Amphioxus EST Neuropeptide Sex steroid Gene expression Reproduction Endocrinology Invertebrate 進化脳遺伝子下垂体

项目摘要

The evolution of the brain-neuron and endocrine organ system from invertebrate to vertebrate has been studied on morphological and molecular aspects in changes of their organs. Amphioxus is the closest invertebrate to vertebrate and considered to possess primitive brain and endocrine organs such as pituitary, thyroid and kidney and so on. Sequences of expressed genes in amphioxus were analyzed by EST conducted from amphioxus nerve cord. Endocrine genes were found from 7,800 EST clones by a homology search. They were neuropeptides including RFamide, neuropeptide Y, and calcitonin and so on, and steroidogenic enzymes including P450scc, P450c17 and 17α, 20β-HSD. Some neuropeptide clones were detected their localizations in nerve cord by in situ hybridization. Genes encoded steroidogenic enzymes were expressed in nerve cells in nerve cord and neurons. Steroidogenic enzymes, 3β-HSD and aromatase were not fond in EST clones, and detected in ovary by using immunohistochemistry. Concentrations of progesterone and estradiol-17β were measured by RIA and increased in breeding season. Opsin gene obtained from EST sequences was studied on the expression in nerve cord and absorbance spectrum. The existence of photoreceptor in nerve cells was suspected the possibility of relations of activation and signaling of neuron induced by photo-stimulation. This study showed the possibility that reproduction in amphioxus was regulated by sex steroids and might stimulate by light through nerve system. In further study, functions of sex steroids in nerve cord and gonad in amphioxus might reveal the neurosteroid function in vertebrate brain.

脑神经元和内分泌器官系统从无脊椎动物到脊椎动物的演变已经研究了其器官变化的形态和分子方面。两栖动物是最接近脊椎动物的无脊椎动物，被认为具有原始的大脑和内分泌器官，例如垂体，甲状腺和肾脏等。通过通过两栖神经索进行EST分析了闪球中表达基因的序列。通过同源性搜索从7,800个EST克隆中发现内分泌基因。它们是神经肽，包括RFAMIDE，神经肽Y和降钙素等，以及类固醇生成酶，包括P450SCC，P450C17和17α，20β-HSD。通过原位杂交检测到一些神经肽克隆在神经绳中的局部定位。基因编码的类固醇生成酶在神经绳和神经元中的神经细胞中表达。在EST克隆中不喜欢类固醇生成酶，3β-HSD和芳香酶，并通过使用免疫组织化学在卵巢中检测到。孕酮和雌二醇17β的浓度通过RIA测量，并在繁殖季节增加。研究了从EST序列获得的Opsin基因在神经绳和吸收光谱中的表达上进行了研究。怀疑神经细胞中光感受器的存在可能是通过光刺激引起的激活和神经元信号的关系的可能性。这项研究表明，两性类固醇的繁殖可能是通过性类固醇调节的，可能会通过神经系统刺激光。在进一步的研究中，神经绳和性腺中性类固醇的功能可能揭示脊椎动物脑中的神经类固醇功能。