Department of Obstetrics and Gynecology, Yong Loo Lin School of Medicine, National University of Singapore, National University Health System, Singapore.
J Proteomics. 2012 Oct 22;75(18):5762-73. doi: 10.1016/j.jprot.2012.07.020. Epub 2012 Jul 25.
In humans, primitive fetal nucleated red blood cells (FNRBCs) are thought to be as vital for embryonic life as their counterpart, adult red blood cells (adult RBCs) are in later-gestation fetuses and adults. Unlike adult RBCs, the identity and functions of FNRBC proteins are poorly understood owing to a scarcity of FNRBCs for proteomic investigations. The study aimed to investigate membrane proteins of this unique cell type. We present here, the first report on the membrane proteome of human primitive FNRBCs investigated by two-dimensional liquid chromatography coupled with mass-spectrometry (2D-LCMS/MS) and bioinformatics analysis. A total of 273 proteins were identified, of which 133 (48.7%) were membrane proteins. We compared our data with membrane proteins of adult RBCs to identify common, and unique, surface membrane proteins. Twelve plasma membrane proteins with transmembrane domains and eight proteins with transmembrane domains but without known sub-cellular location were identified as unique-to-FNRBCs. Except for the transferrin receptor, all other 19 unique-to-FNRBC membrane proteins have never been described in RBCs. Reverse-transcriptase PCR (RT-PCR) and immunocytochemistry validated the 2D-LCMS/MS data. Our findings provide potential surface antigens for separation of primitive FNRBCs from maternal blood for noninvasive prenatal diagnosis, and to understand the biology of these rare cells.
在人类中，原始胎儿有核红细胞（FNRBC）被认为与成人红细胞（adult RBC）在后期胎儿和成人中一样对胚胎生命至关重要。与成人 RBC 不同，由于 FNRBC 数量稀少，用于蛋白质组学研究，因此对其蛋白的特性和功能知之甚少。本研究旨在研究这种独特细胞类型的膜蛋白。我们在此首次报道了通过二维液相色谱-质谱联用（2D-LCMS/MS）和生物信息学分析研究人类原始 FNRBC 膜蛋白组。共鉴定出 273 种蛋白质，其中 133 种（48.7%）为膜蛋白。我们将我们的数据与成人 RBC 的膜蛋白进行了比较，以鉴定共同和独特的表面膜蛋白。鉴定出 12 种具有跨膜结构域的质膜蛋白和 8 种具有跨膜结构域但无已知亚细胞定位的蛋白为 FNRBC 特有。除转铁蛋白受体外，所有其他 19 种 FNRBC 特有膜蛋白在 RBC 中从未被描述过。逆转录酶 PCR（RT-PCR）和免疫细胞化学验证了 2D-LCMS/MS 数据。我们的发现为从母体血液中分离原始 FNRBC 提供了潜在的表面抗原，用于非侵入性产前诊断，并有助于了解这些稀有细胞的生物学特性。
