Brown T L, Moulton B C, Witte D P, Swertfeger D K, Harmony J A
Developmental Biology Graduate Program, Children's Hospital Medical Center, Cincinnati, OH, USA.
Biol Reprod. 1996 Oct;55(4):740-7. doi: 10.1095/biolreprod55.4.740.
The endometrium is a dynamic tissue that responds to hormonal cues and growth factors to accommodate, regulate, and nurture developing embryos. To provide clues about the molecular mechanisms underlying the responsiveness of this tissue, we have begun to identify genes that are expressed at specific stages of early pregnancy. One such gene, apolipoprotein J (apoJ), encodes a secretory glycoprotein capable of binding lipids and membrane-active proteins. Uterine apoJ gene activity was not detected immediately following fertilization, but glandular epithelial expression of apoJ mRNA appeared just before the time of blastocyst implantation and persisted postimplantation. During implantation, uterine luminal epithelial cells also expressed apoJ, but expression was excluded from luminal cells adjacent to the sites of attached blastocysts. ApoJ protein accumulated in the glandular and uterine lumens in proximity to the epithelial cells that expressed apoJ mRNA. We suggest that apoJ expression is a marker of uterine receptivity to blastocyst implantation. Subsequent expression of apoJ message in uterine stromal cell types and in circular muscle myocytes coincided with the onset of decidualization. During this period the myocytes of the longitudinal muscle layer showed no evidence of apoJ mRNA. ApoJ protein was localized to nondecidualized tissue but was not evident in decidualized cells. In contrast, the protein was dispersed throughout both the circular and longitudinal myometrium. In the uteri of hormone-treated females stimulated with oil, apoJ was also expressed during decidualization in stromal cells and in circular myocytes, indicating that signals specifically transmitted from the embryo itself are not responsible for apoJ mRNA accumulation.
子宫内膜是一种动态组织，它对激素信号和生长因子作出反应，以容纳、调节和滋养发育中的胚胎。为了揭示该组织反应性背后的分子机制，我们已开始鉴定在妊娠早期特定阶段表达的基因。载脂蛋白J（apoJ）就是这样一种基因，它编码一种能够结合脂质和膜活性蛋白的分泌性糖蛋白。受精后未立即检测到子宫apoJ基因活性，但在囊胚着床前apoJ mRNA的腺上皮表达出现，并在着床后持续存在。在着床期间，子宫腔上皮细胞也表达apoJ，但着床部位附近的腔细胞不表达。ApoJ蛋白在表达apoJ mRNA的上皮细胞附近的腺腔和子宫腔中积累。我们认为apoJ表达是子宫对囊胚着床接受性的一个标志。随后apoJ信息在子宫基质细胞类型和环形肌细胞中的表达与蜕膜化的开始相一致。在此期间，纵肌层的肌细胞未显示apoJ mRNA的迹象。ApoJ蛋白定位于未蜕膜化组织，但在蜕膜化细胞中不明显。相比之下，该蛋白分散在环形和纵行子宫肌层中。在用油刺激的激素处理雌性动物的子宫中，apoJ在基质细胞和环形肌细胞的蜕膜化过程中也有表达，这表明胚胎本身特异性传递的信号与apoJ mRNA积累无关。
