Bellet D, Lavaissiere L, Mock P, Laurent A, Sabourin J C, Bedossa P, Le Bouteiller P, Frydman R, Troalen F, Bidart J M
Service de Biologie Oncologique, Institut Gustave-Roussy, Villejuif, France.
J Clin Endocrinol Metab. 1997 Sep;82(9):3169-72. doi: 10.1210/jcem.82.9.4359.
Recently, a new member of the insulin gene superfamily termed insulin-like 4 (INSL4) was identified in the human placenta and uterus. The present study investigated whether placenta translates INSL4 mRNA into a putative peptide named early placenta insulin-like (EPIL). Among antibodies elicited against the C chain of pro-EPIL, one antibody (AB7381) was specifically directed against the C chain 59-88 portion, and among those elicited against the A and B chains of EPIL, one antibody (Ab1661) was directed against the A chain 115-139 and the B chain 23-52 portions. Immunohistochemistry based on antibody 7381 to pro-EPIL and antibody 1661 to EPIL demonstrated that the cytotrophoblast from early placenta preferentially expresses the pro-EPIL peptide, whereas the EPIL peptide is expressed by both the cytotrophoblast and the syncytiotrophoblast. At term, the pro-EPIL peptide was detected in villous cytotrophoblast cells, whereas the EPIL peptide was not detected. Moreover, in vitro experiments performed on term placenta showed that the steady state levels of INLS-4 mRNA in the cytotrophoblast are 10 times (one log unit) lower than in the differentiated villous syncytiotrophoblast cells. Taken together, these findings reveal that expression of EPIL peptides in the villous cytotrophoblast is different from that displayed by the syncytiotrophoblast. Finally, these data are the first demonstration that INSL4 mRNA are translated into pro-EPIL and EPIL peptides.
最近，在人胎盘和子宫中发现了胰岛素基因超家族的一个新成员，称为胰岛素样4（INSL4）。本研究调查了胎盘是否将INSL4 mRNA翻译成一种假定的肽，即早期胎盘胰岛素样肽（EPIL）。在针对前体EPIL的C链产生的抗体中，一种抗体（AB7381）特异性针对C链59 - 88部分，在针对EPIL的A链和B链产生的抗体中，一种抗体（Ab1661）针对A链115 - 139和B链23 - 52部分。基于针对前体EPIL的抗体7381和针对EPIL的抗体1661的免疫组织化学表明，早期胎盘的细胞滋养层优先表达前体EPIL肽，而EPIL肽由细胞滋养层和合胞体滋养层共同表达。足月时，在绒毛细胞滋养层细胞中检测到前体EPIL肽，而未检测到EPIL肽。此外，对足月胎盘进行的体外实验表明，细胞滋养层中INLS - 4 mRNA的稳态水平比分化的绒毛合胞体滋养层细胞低10倍（一个对数单位）。综上所述，这些发现揭示了绒毛细胞滋养层中EPIL肽的表达与合胞体滋养层不同。最后，这些数据首次证明INSL4 mRNA被翻译成前体EPIL和EPIL肽。
