Cloning of two tryptophan hydroxylase genes expressed in the diencephalon of the developing zebrafish brain
Cloning of two tryptophan hydroxylase genes expressed in the diencephalon of the developing zebrafish brain
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DOI：
10.1016/s0925-4773(03)00119-9
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发表时间：
2002-12-01
影响因子：
2.6
通讯作者：
Bally-Cuif, Laure
中科院分区：
文献类型：
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作者：
Bellipanni, Gianfranco;Rink, Elke;Bally-Cuif, Laure
单胺5-羟色胺（5-HT）在所有动物门中都发挥着关键的神经调节作用，但对5-HT能系统的发育和功能仍不完全清楚。斑马鱼是一个很好的模式，以解决这个问题，因为它是服从遗传，分子和胚胎学研究的组合。为了表征斑马鱼中色氨酸能神经元的组织，我们克隆了两个编码不同形式的色氨酸羟化酶（Tph）的cDNA，色氨酸羟化酶是5-羟色胺合成的限速酶。我们在这里报告的模式，这两个基因的表达与免疫反应TH和5-羟色胺核在发育中的斑马鱼胚胎和早期幼虫。tphD 1的表达开始于受精后22小时（hpf）在骨骺和基底脊髓细胞。表达在骨骺中持续至少4天（dpf）。在48 hpf和3 dpf之间，tphD 1表达起始于视网膜无长突细胞和基底间脑内的受限视前核和后结节核。在3和4 dpf，tphD 1的表达是新的启动在尾部下丘脑和鳃弓相关的神经元。tphD 2 mRNA在限制性视前核中瞬时检测到（在30体节和32 hpf之间）。在前中枢神经系统内tphD 1或D2表达的所有位点也对5-HT呈免疫反应性，但对TH不呈阳性。然而，tphD基因在中缝核中均不表达，这表明在斑马鱼中存在另外的tph基因来解释该位置的5-HT合成。tphD 1，tphD 2和5-羟色胺在斑马鱼间脑的共同表达出现在哺乳动物，间脑5-羟色胺的结果从再摄取，而不是从本地生产的情况形成鲜明对比。(c)2003爱思唯尔科学爱尔兰有限公司保留所有权利。
The monoamine serotonin (5-HT) exerts key neuromodulatory activities in all animal phyla, but the development and function of the serotonergic system is still incompletely understood. The zebrafish Danio rerio is an excellent model to approach this question since it is amenable to a combination of genetic, molecular and embryological studies. In order to characterize the organization of serotonergic neurons in the zebrafish we cloned two cDNAs encoding distinct forms of tryptophan hydroxylase (Tph), the rate-limiting enzyme in serotonin synthesis. We report here the pattern of expression of these two genes in relation with immunoreactive TH and 5-HT nuclei in the developing zebrafish embryo and early larva. tphD1 expression starts at 22 h post-fertilization (hpf) in the epiphysis and in basal spinal cells. Expression persists in the epiphysis until at least 4 days (dpf). Between 48 hpf and 3 dpf, tphD1 expression is initiated in retinal amacrine cells and in restricted preoptic and posterior tubercular nuclei within the basal diencephalon. At 3 and 4 dpf, tphD1 expression is newly initiated in the caudal hypothalamus and in branchial arches-associated neurons. tphD2 mRNA is detected transiently (between 30 somites and 32 hpf) in a restricted preoptic nucleus. All sites of tphD1 or D2 expression within the anterior central nervous system are also immunoreactive for 5-HT, but are not positive for TH. However, neither tphD gene is expressed in raphe nuclei, suggesting that additional tph gene(s) exist in zebrafish to account for 5-HT synthesis in that location. The co-expression of tphD1, tphD2 and 5-HT in the zebrafish diencephalon appears in striking contrast to the situation in mammals, where diencephalic serotonin results from re-uptake rather than from local production. (c) 2003 Elsevier Science Ireland Ltd. All rights reserved.