Tsark E C, Adamson E D, Withers G E, Wiley L M
Division of Reproductive Biology and Medicine, University of California at Davis 95616-8615, USA.
Mol Reprod Dev. 1997 Jul;47(3):271-83. doi: 10.1002/(SICI)1098-2795(199707)47:3<271::AID-MRD6>3.0.CO;2-I.
Amphiregulin (Ar) is an EGF receptor ligand that functions to modulate the growth of both normal and malignant epithelial cells. We asked whether mouse preimplantation embryos express Ar, and if so, what the function of Ar is during preimplantation development. We used RT-PCR to show expression of Ar mRNA in mouse blastocysts, and using a polyclonal anti-Ar antibody and indirect immunofluorescence, we detected the presence of Ar protein in morula- and blastocyst-stage embryos. Ar protein was present in both the cytoplasm and nucleus in both morulae- and blastocyst-stage embryos, which is similar to Ar distribution in other cell types. Embryos cultured in Ar developed into blastocysts more quickly and also exhibited increased cell numbers compared to control embryos. In addition, 4-cell stage embryos cultured in an antisense Ar phosphorothioate-modified oligodeoxynucleotide (S-oligo) for 48 hr exhibited slower rates of blastocyst formation and reduced embryo cell numbers compared to embryos exposed to a random control S-oligo. TGF-alpha significantly improved blastocyst formation, but not cell numbers, for embryos cultured in the antisense Ar S-oligo. From these observations, we propose that Ar may function as an autocrine growth factor for mouse preimplantation embryos by promoting blastocyst formation and embryo cell number. We also propose that blastocyst formation is stimulated by Ar and TGF-alpha, while Ar appears to exert a greater stimulatory effect on cell proliferation than does TGF-alpha in these embryos.
双调蛋白（Ar）是一种表皮生长因子（EGF）受体配体，其作用是调节正常和恶性上皮细胞的生长。我们研究了小鼠植入前胚胎是否表达Ar，如果表达，那么Ar在植入前发育过程中的功能是什么。我们使用逆转录聚合酶链反应（RT-PCR）来显示Ar信使核糖核酸（mRNA）在小鼠囊胚中的表达，并使用多克隆抗Ar抗体和间接免疫荧光法，在桑葚胚和囊胚期胚胎中检测到了Ar蛋白的存在。Ar蛋白在桑葚胚和囊胚期胚胎的细胞质和细胞核中均有存在，这与Ar在其他细胞类型中的分布情况相似。与对照胚胎相比，在含有Ar的培养液中培养的胚胎发育成囊胚的速度更快，并且细胞数量也有所增加。此外，与暴露于随机对照硫代磷酸酯修饰寡脱氧核苷酸（S-寡核苷酸）的胚胎相比，在反义Ar硫代磷酸酯修饰寡脱氧核苷酸（S-寡核苷酸）中培养48小时的4细胞期胚胎，其囊胚形成率较低，胚胎细胞数量减少。对于在反义Ar S-寡核苷酸中培养的胚胎，转化生长因子-α（TGF-α）显著改善了囊胚形成，但没有增加细胞数量。基于这些观察结果，我们认为Ar可能通过促进囊胚形成和胚胎细胞数量，作为小鼠植入前胚胎的自分泌生长因子。我们还认为，Ar和TGF-α刺激了囊胚形成，而在这些胚胎中，Ar对细胞增殖的刺激作用似乎比TGF-α更大。
