Cell migration is essential during development, regeneration, homeostasis, and disease. Depending on the microenvironment, cells use different mechanisms to migrate. Yet, all modes of migration require the establishment of an intracellular front–rear polarity axis for directional movement. Although front–rear polarity can be easily identified in in vitro conditions, its assessment in vivo by live‐imaging is challenging due to tissue complexity and lack of reliable markers. Here, we describe a novel and unique double fluorescent reporter mouse line to study front–rear cell polarity in living tissues, called GNrep. This mouse line simultaneously labels Golgi complexes and nuclei allowing the assignment of a nucleus‐to‐Golgi axis to each cell, which functions as a readout for cell front–rear polarity. As a proof‐of‐principle, we validated the efficiency of the GNrep line using an endothelial‐specific Cre mouse line. We show that the GNrep labels the nucleus and the Golgi apparatus of endothelial cells with very high efficiency and high specificity. Importantly, the features of fluorescent intensity and localization for both mCherry and eGFP fluorescent intensity and localization allow automated segmentation and assignment of polarity vectors in complex tissues, making GNrep a great tool to study cell behavior in large‐scale automated analyses. Altogether, the GNrep mouse line, in combination with different Cre recombinase lines, is a novel and unique tool to study of front–rear polarity in mice, both in fixed tissues or in intravital live imaging. This new line will be instrumental to understand cell migration and polarity in development, homeostasis, and disease.

中文翻译：

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GNrep鼠标：用于前后细胞极性的报告基因鼠标。

在发育，再生，体内平衡和疾病过程中，细胞迁移至关重要。取决于微环境，细胞使用不同的机制进行迁移。但是，所有迁移方式都需要为定向运动建立一个细胞内前后极性轴。尽管可以在体外条件下轻松识别前后极性，但可以在体内对其进行评估由于组织复杂且缺乏可靠的标记物，实时成像的挑战性很大。在这里，我们描述了一种新颖独特的双荧光报告基因小鼠系，用于研究活体组织GNrep的前后细胞极性。这条小鼠线同时标记了高尔基体和细胞核，从而允许每个细胞分配一个核到高尔基体轴，作为细胞前后极性的读数。作为原理证明，我们使用内皮特异性Cre小鼠品系验证了GNrep品系的效率。我们表明，GNrep以非常高的效率和高的特异性标记内皮细胞的细胞核和高尔基体。重要的，mCherry和eGFP的荧光强度和定位特性可以实现复杂组织中极性矢量的自动分割和分配，从而使GNrep成为研究大规模自动化分析中细胞行为的理想工具。总而言之，GNrep小鼠系与不同的Cre重组酶系结合使用，是一种新颖且独特的工具，可用于研究固定组织或活体实时成像中小鼠的前后极性。这条新路线将有助于理解细胞在发育，体内稳态和疾病中的迁移和极性。是在固定组织或活体内实时成像中研究小鼠前后极性的新颖独特工具。这条新路线将有助于理解细胞在发育，体内稳态和疾病中的迁移和极性。是在固定组织或活体内实时成像中研究小鼠前后极性的新颖独特工具。这条新路线将有助于理解细胞在发育，体内稳态和疾病中的迁移和极性。