Heterogeneous nuclear ribonucleoprotein L (hnRNPL) is a conserved RNA binding protein (RBP) that plays an important role in the alternative splicing of gene transcripts, and thus in the generation of specific protein isoforms. Global deficiency in hnRNPL in mice results in preimplantation embryonic lethality at embryonic day (E) 3.5. To begin to understand the contribution of hnRNPL-regulated pathways in the normal development of the embryo and placenta, we determined hnRNPL expression profile and subcellular localization throughout development. Proteome and Western blot analyses were employed to determine hnRNPL abundance between E3.5 and E17.5. Histological analyses supported that the embryo and implantation site display distinct hnRNPL localization patterns. In the fully developed mouse placenta, nuclear hnRNPL was observed broadly in trophoblasts, whereas within the implantation site a discrete subset of cells showed hnRNPL outside the nucleus. In the first-trimester human placenta, hnRNPL was detected in the undifferentiated cytotrophoblasts, suggesting a role for this factor in trophoblast progenitors. Parallel in vitro studies utilizing Htr8 and Jeg3 cell lines confirmed expression of hnRNPL in cellular models of human trophoblasts. These studies [support] coordinated regulation of hnRNPL during the normal developmental program in the mammalian embryo and placenta.

异质核核糖核蛋白 L (hnRNPL) 是一种保守的 RNA 结合蛋白 (RBP)，在基因转录本的选择性剪接中发挥着重要作用，从而在特定蛋白质亚型的生成中发挥着重要作用。小鼠中 hnRNPL 的整体缺乏会导致胚胎第 3.5 天的植入前胚胎死亡。为了开始了解 hnRNPL 调控途径在胚胎和胎盘正常发育中的贡献，我们确定了 hnRNPL 表达谱和整个发育过程中的亚细胞定位。采用蛋白质组和蛋白质印迹分析来确定 E3.5 和 E17.5 之间的 hnRNPL 丰度。组织学分析支持胚胎和植入位点显示出不同的 hnRNPL 定位模式。在完全发育的小鼠胎盘中，在滋养层细胞中广泛观察到核 hnRNPL，而在植入位点内，离散的细胞子集在核外显示 hnRNPL。在妊娠早期的人胎盘中，在未分化的细胞滋养层细胞中检测到 hnRNPL，表明该因子在滋养层祖细胞中发挥作用。平行线利用 Htr8 和 Jeg3 细胞系的体外研究证实了 hnRNPL 在人类滋养层细胞模型中的表达。这些研究支持哺乳动物胚胎和胎盘正常发育过程中 hnRNPL 的协调调节。