Platelet endothelial cell adhesion molecule 1 (PECAM‐1) is an adhesion and signaling receptor that is expressed on endothelial and hematopoietic cells and plays important roles in angiogenesis, vascular permeability, and regulation of cellular responsiveness. To better understanding the tissue specificity of PECAM‐1 functions, we generated mice in which PECAM1, the gene encoding PECAM‐1, could be conditionally knocked out. A targeting construct was created that contains loxP sites flanking PECAM1 exons 1 and 2 and a neomycin resistance gene flanked by flippase recognition target (FRT) sites that was positioned upstream of the 3′ loxP site. The targeting construct was electroporated into C57BL/6 embryonic stem (ES) cells, and correctly targeted ES cells were injected into C57BL/6 blastocysts, which were implanted into pseudo‐pregnant females. Resulting chimeric animals were bred with transgenic mice expressing Flippase 1 (FLP1) to remove the FRT‐flanked neomycin resistance gene and mice heterozygous for the floxed PECAM1 allele were bred with each other to obtain homozygous PECAM1 ^flox/flox offspring, which expressed PECAM‐1 at normal levels and had no overt phenotype. PECAM1 ^flox/flox mice were bred with mice expressing Cre recombinase under the control of the SRY‐box containing gene 2 (Sox2Cre) promoter to delete the floxed PECAM1 allele in offspring (Sox2Cre;PECAM1 ^del/WT), which were crossbred to generate Sox2Cre; PECAM1 ^del/del offspring. Sox2Cre; PECAM1 ^del/del mice recapitulated the phenotype of conventional global PECAM‐1 knockout mice. PECAM1 ^flox/flox mice will be useful for studying distinct roles of PECAM‐1 in tissue specific contexts and to gain insights into the roles that PECAM‐1 plays in blood and vascular cell function.

中文翻译：

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PECAM-1（CD31）条件敲除小鼠的产生。

血小板内皮细胞粘附分子1（PECAM-1）是一种粘附和信号受体，在内皮细胞和造血细胞上表达，在血管生成，血管通透性和细胞反应性调节中起着重要作用。为了更好地了解PECAM-1功能的组织特异性，我们制备了小鼠，其中可以有条件地敲除编码PECAM-1的基因PECAM1。靶向构建体被创建包含loxP位点侧翼PECAM1外显子1和2和新霉素抗性基因的侧翼由翻转酶识别目标（FRT）位点被定位在3'上游的loxP现场。将靶向构建体电穿孔到C57BL / 6胚胎干（ES）细胞中，然后将正确靶向的ES细胞注射到C57BL / 6胚泡中，然后将其植入假孕雌性中。将产生的嵌合动物与表达Flippase 1（FLP1）的转基因小鼠一起饲养，以去除FRT侧翼的新霉素抗性基因，并将杂合了PECAM1等位基因的小鼠进行繁育，以获得纯合的PECAM1 ^{flox / flox}后代，该后代表达PECAM-1处于正常水平，没有明显的表型。在含有SRY-box的基因2（Sox2Cre）启动子的控制下，用表达Cre重组酶的小鼠饲养PECAM1 ^{flox / flox}小鼠，以删除其 后代的PECAM1等位基因（Sox2Cre; PECAM1 ^{del / WT}），杂交产生Sox2Cre；PECAM1 ^{del / del}后代。Sox2Cre; PECAM1 ^{del / del}小鼠概括了常规全局PECAM-1基因敲除小鼠的表型。PECAM1 ^{flox / flox}小鼠将有助于研究PECAM-1在组织特定背景下的独特作用，并深入了解PECAM-1在血液和血管细胞功能中的作用。