PDF(Pubmed)
Abstract：
The axon initial segment (AIS) constitutes not only the site of action potential initiation, but also a hub for activity-dependent modulation of output generation. Recent studies shedding light on AIS function used predominantly post-hoc approaches since no robust murine in vivo live reporters exist. Here, we introduce a reporter line in which the AIS is intrinsically labeled by an ankyrin-G-GFP fusion protein activated by Cre recombinase, tagging the native Ank3 gene. Using confocal, superresolution, and two-photon microscopy as well as whole-cell patch-clamp recordings in vitro, ex vivo, and in vivo, we confirm that the subcellular scaffold of the AIS and electrophysiological parameters of labeled cells remain unchanged. We further uncover rapid AIS remodeling following increased network activity in this model system, as well as highly reproducible in vivo labeling of AIS over weeks. This novel reporter line allows longitudinal studies of AIS modulation and plasticity in vivo in real-time and thus provides a unique approach to study subcellular plasticity in a broad range of applications.
摘要：
轴突起始段(AIS)不仅构成动作电位起始位点,也是输出生成的活动相关调制的集线器。最近的研究揭示了AIS功能，主要使用事后方法，因为不存在健壮的小鼠体内活报道分子。这里,我们介绍了一个报告基因，其中AIS由Cre重组酶激活的Ankyrin-G-GFP融合蛋白内在标记，标记天然Ank3基因。使用共聚焦，超分辨率,和双光子显微镜以及体外全细胞膜片钳记录，离体,在体内，我们证实AIS的亚细胞支架和标记细胞的电生理参数保持不变。在这个模型系统中，我们进一步发现了随着网络活动的增加，AIS的快速重塑，以及在几周内AIS的体内标记高度可重复。这种新颖的报告线允许实时地对体内AIS调制和可塑性进行纵向研究，因此提供了一种独特的方法来研究广泛的应用中的亚细胞可塑性。
