Tissue‐specific inducible Cre recombinase mouse lines allow precise genetic manipulations in spatiotemporal manners and are pivotal for functional studies of genes during development and in adults. Growth factor independence 1 (GFI1) is an essential transcription factor expressed in the hair cells of mouse inner ear and Gfi1 locus serves as an excellent anchor site to drive the expression of inducible Cre recombinase in mouse inner hair cells. In this study, we have generated Gfi1‐P2A‐GFP‐CreERT2 (Gfi1‐GCE) knock‐in mouse line by in‐frame fusion of a self‐cleaving GCE to the C‐terminus of GFI1. We have shown that as predicted, the expression of GCE and GFI1 was detected specifically in the cytosol and nuclei of hair cells, respectively, of uninduced Gfi1‐GCE mice, suggesting the successful cleavage and simultaneous expression of GFI1 and GCE. In addition, the in‐frame fusion of the self‐cleaving GCE does not interrupt the function of Gfi1 in the inner ear. Administration of tamoxifen leads to nuclear translocation of GCE and results in an efficient activation of tdTomato reporter gene expression specifically in most hair cells throughout development and in adults. Thus, this inducible Gfi1‐GCE mouse line is a highly efficient Cre deleter and is suitable for gene manipulation in developing and adult inner ear hair cells.

中文翻译：

---

用于小鼠内耳毛细胞特异性基因操作的 Gfi1-GCE 诱导型 Cre 系。

组织特异性诱导型 Cre 重组酶小鼠品系允许以时空方式进行精确的遗传操作，对于发育过程中和成人的基因功能研究至关重要。生长因子独立 1 (GFI1) 是一种在小鼠内耳毛细胞中表达的重要转录因子，Gfi1基因座是驱动小鼠内毛细胞中诱导型 Cre 重组酶表达的极佳锚定位点。在这项研究中，我们通过自切割 GCE 与 GFI1 C 端的框内融合产生了Gfi1-P2A-GFP-CreERT2 ( Gfi1-GCE ) 敲入小鼠系。我们已经表明，正如预测的那样，GCE 和 GFI1 的表达分别在未诱导的毛细胞的胞质溶胶和细胞核中被特异性检测到。Gfi1-GCE小鼠，表明 GFI1 和 GCE 的成功切割和同时表达。此外，自切割 GCE 的帧内融合不会中断Gfi1在内耳中的功能。给予他莫昔芬会导致 GCE 的核转位，并导致 tdTomato 报告基因表达的有效激活，特别是在整个发育过程和成人中的大多数毛细胞中。因此，这种诱导型Gfi1-GCE小鼠系是一种高效的 Cre 删除子，适用于发育和成年内耳毛细胞的基因操作。