Patterning of dopaminergic neurotransmitter identity among Caenorhabditis elegans ray sensory neurons by a TGFbeta family signaling pathway and a Hox gene.
Patterning of dopaminergic neurotransmitter identity among Caenorhabditis elegans ray sensory neurons by a TGFbeta family signaling pathway and a Hox gene.
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发表时间：
1999-12
期刊：
影响因子：
4.6
通讯作者：
R. Lints;S. W. Emmons
中科院分区：
文献类型：
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作者：
R. Lints;S. W. Emmons
我们研究了秀丽隐杆线虫雄性射线感觉神经元中多巴胺表达模式的机制。多巴胺由九对射线中的三对中的A型感觉神经元表达。我们使用酪氨酸羟化酶报告基因的表达以及多巴胺的直接测定来研究多巴胺能细胞命运的遗传要求。在影响TGF β家族信号传导途径（DBL-1途径）的功能丧失突变体中，多巴胺能特性被更广泛的射线子集不规则地采用。异位表达的途径配体，DBL-1，从热休克驱动的转基因的结果，通过射线3-9多巴胺能的身份，射线1和2是难治性的。因此，射线相对于其由DBL-1途径信号诱导的能力被预图案化。温度敏感的II型受体突变体的温度变化实验以及热休克诱导实验表明，DBL-1通路在射线神经元出生和开始分化之前从两代细胞延伸到一代细胞的间隔期间起作用。在AbdominalB类Hox基因egl-5的突变体中，通常表达EGL-5的射线不采用多巴胺能命运，并且当DBL-1由热休克驱动的dbl-1转基因提供时不能被诱导表达DA。因此，egl-5是使射线的子集能够采用多巴胺能身份所必需的，而DBL-1途径信号的功能是模式化该能力的实现。
We have investigated the mechanism that patterns dopamine expression among Caenorhabditis elegans male ray sensory neurons. Dopamine is expressed by the A-type sensory neurons in three out of the nine pairs of rays. We used expression of a tyrosine hydroxylase reporter transgene as well as direct assays for dopamine to study the genetic requirements for adoption of the dopaminergic cell fate. In loss-of-function mutants affecting a TGFbeta family signaling pathway, the DBL-1 pathway, dopaminergic identity is adopted irregularly by a wider subset of the rays. Ectopic expression of the pathway ligand, DBL-1, from a heat-shock-driven transgene results in adoption of dopaminergic identity by rays 3-9; rays 1 and 2 are refractory. The rays are therefore prepatterned with respect to their competence to be induced by a DBL-1 pathway signal. Temperature-shift experiments with a temperature-sensitive type II receptor mutant, as well as heat-shock induction experiments, show that the DBL-1 pathway acts during an interval that extends from two to one cell generation before ray neurons are born and begin to differentiate. In a mutant of the AbdominalB class Hox gene egl-5, rays that normally express EGL-5 do not adopt dopaminergic fate and cannot be induced to express DA when DBL-1 is provided by a heat-shock-driven dbl-1 transgene. Therefore, egl-5 is required for making a subset of rays capable of adopting dopaminergic identity, while the function of the DBL-1 pathway signal is to pattern the realization of this capability.