We have previously reported the isolation and characterization of a novel endothelial-restricted gene, Egfl7, that encodes a secreted protein of about 30-kDa. We and others demonstrated that Egfl7 is highly expressed by endothelial cells during embryonic development and becomes down-regulated in the adult vasculature. In the present paper, we show that during mouse embryonic development, Egfl7 is also expressed by primordial germ cells (PGC). Expression is down-regulated when PGCs differentiate into pro-spermatogonia and oogonia, and by 15.5 dpc Egfl7 can no longer be detected in the germ line of both sexes. Notably, Egfl7 is again transiently up-regulated in germ cells of the adult testis. In contrast, expression in the ovary remains limited to the vascular endothelium. Our results provide the first evidence of a non-endothelial expression of EGFL7 and suggest distinctive roles for Egfl7 in vascular development and germ cell differentiation.

中文翻译：

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EGFL7 在原始生殖细胞和成人卵巢和睾丸中的表达。

我们以前曾报道过一种新型内皮限制基因 Egfl7 的分离和表征，该基因编码约 30 kDa 的分泌蛋白。我们和其他人证明 Egfl7 在胚胎发育过程中由内皮细胞高度表达，并在成人脉管系统中下调。在本文中，我们展示了在小鼠胚胎发育过程中，Egfl7 也由原始生殖细胞 (PGC) 表达。当 PGC 分化为原精原细胞和卵原细胞时，表达下调，并且到 15.5 dpc，在两性的生殖系中都不再检测到 Egfl7。值得注意的是，Egfl7 在成人睾丸的生殖细胞中再次瞬时上调。相比之下，卵巢中的表达仍然仅限于血管内皮。