Objective: To perform the modulation of an assay system for the sensory integration of 2 sensory stimuli that inhibit each other.
Methods: The assay system for assessing the integrative response to 2 reciprocally-inhibitory sensory stimuli was modulated by changing the metal ion barrier. Moreover, the hen-1, ttx-3 and casy-1 mutants having known defects in integrative response were used to evaluate the modulated assay systems. Based on the examined assay systems, new genes possibly involved in the sensory integration control were identified.
Results: In the presence of different metal ion barriers and diacetyl, locomotion behaviors, basic movements, pan-neuronal, cholinergic and GABAergic neuronal GFP expressions, neuronal development, structures of sensory neurons and interneurons, and stress response of nematodes in different regions of examined assay systems were normal, and chemotaxis toward different concentrations of diacetyl and avoidance of different concentrations of metal ions were inhibited. In the first group, most of the nematodes moved to diacetyl by crossing the barrier of Fe(2+), Zn(2+), or Mn(2+). In the second group, almost half of the nematodes moved to diacetyl by crossing the barrier of Ag(+), Cu(2+), Cr(2+), or Cd(2+). In the third group, only a small number of nematodes moved to diacetyl by crossing the barrier of Pb(2+) or Hg(2+). Moreover, when nematodes encountered different metal ion barriers during migration toward diacetyl, the percentage of nematodes moving back and then turning and that of nematodes moving straight to diacetyl were very different. With the aid of examined assay systems, it was found that mutations of fsn-1 that encodes a F-box protein, and its target scd-2 that encodes a receptor tyrosine kinase, caused severe defects in integrative response, and the sensory integration defects of fsn-1 mutants were obviously inhibited by scd-2 mutation.
Conclusion: Based on the nematode behaviors in examined assay systems, 3 groups of assay systems were obtained. The first group may be helpful in evaluating or identifying the very subtle deficits in sensory integration, and the third group may be useful for the final confirmation of sensory integration defects of mutants identified in the first or the second group of assay systems. Furthermore, the important association of sensory integration regulation with stabilization or destabilization of synaptic differentiation may exist in C. elegans.
方法: 在分析体系中, 尝试通过改变金属离子墙类型来改变动物对两种相互抑制刺激信号的整合。 此外, 用3种已经被证实有感觉信号整合缺陷的hen-1、 ttx-3和casy-3突变体评估调整后的分析体系。 借助新建立的分析体系, 进一步鉴定可能参与动物感觉信号整合的基因。
结果: 在分析系统不同区域, 秀丽线虫的运动行为、 基本运动能力、 神经发育与应激反应均正常。 各种浓度的金属离子墙能抑制线虫对不同浓度丁二酮的趋向性。 此外, 各种浓度的丁二酮也能抑制线虫对不同浓度金属离子的规避性。 大多数的秀丽线虫越过Fe2+、 Zn2+或Mn2+墙趋向丁二酮(第1 类)约有一半数量的秀丽线虫会越过Ag+、 Cu2+、 Cr2+或Cd2+墙趋向丁二酮(第2类);只有很少数量的秀丽线虫会越过Pb2+或Hg2+墙趋向丁二酮(第3类)。 此外, 在向丁二酮趋向过程中, 当秀丽线虫遇到不同金属离子墙时, 其做出向后运动而后趋向于丁二酮的比例与其直接趋向于丁二酮运动的比例呈现出差异。 借助于建立的分析体系, 可观察到编码F-box蛋白的fsn-1基因的突变体以及编码其靶点酪氨酸激酶受体的scd-2基因的突变体均表现出严重的感觉信号整合缺陷, 且fsn-1突变体的感觉信号整合缺陷可显著被scd-2突变抑制。
结论: 基于模型中的动物感觉信号整合行为, 本研究中使用的分析系统可分为3类。 第1类分析系统可能有助于评估或鉴定突变体中微弱的感觉信号整合缺陷, 而第3类分析系统可能有助于进一步确认第1类及第2类分析系统鉴定的感觉信号整合缺陷。 此外, 秀丽线虫中突触组装分化的稳定或去稳定化可能与感觉信号整合的调控存在密切的联系。