Identification and Characterization of a Novel Regulator of Dopamine Signaling

描述（由申请人提供）：多巴胺（DA）信号调节多种行为，包括模式化运动活动、奖励寻求和执行功能。可卡因敏感的DA转运体（DAT）是突触前DA稳态的关键决定因素，也是限制DA在空间和时间上的作用的关键因素。因此，多巴胺信号被破坏被认为有助于多种大脑疾病的风险，包括精神分裂症，注意力缺陷多动障碍（ADHD），成瘾和帕金森病。不幸的是，正向遗传学方法，可以阐明的分子网络的DA信号和DAT的控制是难以实施的哺乳动物。我们发现，C。当蠕虫被置于水中时，线虫dat-1基因导致高度渗透的、DA信号传导依赖的麻痹表型，我们称之为游泳诱导的麻痹（Swip）。dat-1动物的Swip可以通过与携带cat-1（哺乳动物囊泡单胺转运蛋白（VMAT）的直系同源物，cat-2（其编码酪氨酸羟化酶））的功能丧失等位基因的动物杂交以及通过用VMAT抑制剂利血平处理动物来挽救。当dat-1动物与缺乏特异性突触后D2型多巴胺受体（dop-3）的动物杂交时，也可以看到Swip行为的拯救。最近，我们的实验室实施了正向遗传筛选，以确定可以通过利血平以及与其他DA信号突变体杂交来拯救的Swip系。从这个屏幕上，我已经帮助确定动物轴承新的，功能丧失dat-1等位基因，以及突变体，映射到基因座，缺乏已知的贡献者DA信号。一个这样的突变体，swip 13（vt 32），显示降低DA水平，类似于dat-1敲除动物，并表现出对神经毒素6-OHDA的抗性，这需要DAT-1活性的DA神经元输入。由于Swip是一种高多巴胺能表型，因此swip 13（vt 32）动物的DA含量降低和6-OHDA敏感性丧失表明，SWIP 13蛋白可能调节DAT表达、运输或活性。我最近已经确定了swip 13表型的基因，并发现它在哺乳动物中高度保守。在这里，我建议调查如何swip 13调节DA信号在C。与Blakely实验室合作研究相对未研究的swip 13直系同源物ERK 7/8。

DESCRIPTION (provided by applicant): Dopamine (DA) signaling modulates multiple behaviors including patterned motor activity, reward seeking and executive function. The cocaine-sensitive DA transporter (DAT) is a critical determinant of presynaptic DA homeostasis as well as in limiting the actions of DA in space and time. Consequentially, disrupted DA signaling is thought to contribute to risk for multiple brain disorders including schizophrenia, attention-deficit hyperactivity disorder (ADHD), addiction and Parkinson's disease. Unfortunately, forward genetic approaches that can elucidate the molecular networks impinging on the control of DA signaling and DAT are difficult to implement in mammals. We have found that ablation of the C. elegans dat-1 gene results in a highly-penetrant, DA signaling-dependent, paralysis phenotype when worms are placed in water, a phenotype we term Swimming- Induced Paralysis (Swip). The Swip of dat-1 animals can be rescued by crosses to animals bearing loss of function alleles of cat-1, ortholog of mammalian vesicular monoamine transporters (VMATs), cat-2, which encodes tyrosine hydroxylase, as well as by treatment of animals with the VMAT inhibitor reserpine. Rescue of Swip behavior is also seen when dat-1 animals are crossed to animals lacking a specific, postsynaptic D2-type dopamine receptor (dop-3). Recently, our lab implemented a forward genetic screen to identify Swip lines that can be rescued by reserpine as well as by crosses to other DA signaling mutants. From this screen, I have helped identify animals bearing novel, loss of function dat-1 alleles, as well as mutants that map to loci that lac known contributors to DA signaling. One such mutant, swip13 (vt32), displays reduced DA levels, similar to dat-1 knockout animals, and exhibits resistance to the neurotoxin 6-OHDA, which requires DAT-1 activity for DA neuron import. As Swip is a hyperdopaminergic phenotype, the reduced DA content of swip13 (vt32) animals and loss of 6-OHDA sensitivity suggest that the SWIP13 protein may regulate DAT expression, trafficking or activity. I have recently identified the gene accounting for the swip13 phenotype, and found it to be highly conserved in mammals. Here, I propose to investigate how this swip13 regulates DA signaling in C. elegans with Blakely lab and collaborative studies examining the relatively unstudied swip13 ortholog ERK 7/8.