Department of Biology, York University, Toronto, ON M3J 1P3, Canada.
Center of Vision Research, York University, Toronto, ON M3J 1P3, Canada.
Int J Mol Sci. 2021 Oct 29;22(21):11750. doi: 10.3390/ijms222111750.
Pannexin1 (Panx1) can form ATP-permeable channels that play roles in the physiology of the visual system. In the zebrafish two ohnologs of Panx1, Panx1a and Panx1b, have unique and shared channel properties and tissue expression patterns. Panx1a channels are located in horizontal cells of the outer retina and modulate light decrement detection through an ATP/pH-dependent mechanisms and adenosine/dopamine signaling. Here, we decipher how the strategic localization of Panx1b channels in the inner retina and ganglion cell layer modulates visually evoked motor behavior. We describe a knockout model generated by TALEN technology. The RNA-seq analysis of 6 days post-fertilization larvae is confirmed by real-time PCR and paired with testing of locomotion behaviors by visual motor and optomotor response tests. We show that the loss of Panx1b channels disrupts the retinal response to an abrupt loss of illumination and it decreases the larval ability to follow leftward direction of locomotion in low light conditions. We concluded that the loss of Panx1b channels compromises the final output of luminance as well as motion detection. The Panx1b protein also emerges as a modulator of the circadian clock system. The disruption of the circadian clock system in mutants suggests that Panx1b could participate in non-image forming processes in the inner retina.
Pannexin1 (Panx1) 可以形成 ATP 通透通道，在视觉系统的生理学中发挥作用。在斑马鱼中，Panx1 的两个同源物 Panx1a 和 Panx1b 具有独特和共享的通道特性和组织表达模式。Panx1a 通道位于外视网膜的水平细胞中，通过 ATP/pH 依赖机制和腺苷/多巴胺信号调节光衰减检测。在这里，我们阐明了 Panx1b 通道在视网膜内层和神经节细胞层中的战略定位如何调节视觉诱发的运动行为。我们描述了一种由 TALEN 技术产生的基因敲除模型。通过实时 PCR 对 6 天孵化后的幼虫进行 RNA-seq 分析，并通过视觉运动和光觉反应测试进行运动行为测试进行验证。我们表明，Panx1b 通道的缺失破坏了对光突然消失的视网膜反应，并降低了幼虫在低光照条件下跟随向左运动方向的能力。我们得出结论，Panx1b 通道的缺失损害了亮度以及运动检测的最终输出。Panx1b 蛋白也成为光感受系统生物钟的调节剂。突变体中生物钟系统的破坏表明 Panx1b 可能参与视网膜内层的非图像形成过程。
