Nielsen Julie S, McNagny Kelly M
Trev and Joyce Deeley Research Centre, British Columbia Cancer Agency, 2410 Lee Avenue, Victoria, BC, Canada V8R 6V5.
J Cell Sci. 2008 Nov 15;121(Pt 22):3683-92. doi: 10.1242/jcs.037507.
For almost 30 years, the cell-surface protein CD34 has been widely used as a marker to assist in the identification and Summary isolation of hematopoietic stem cells (HSCs) and progenitors in preparation for bone-marrow transplantation. In addition, it has increasingly been used as a marker to help identify other tissue-specific stem cells, including muscle satellite cells and epidermal precursors. Despite its utility as a stem-cell marker, however, the function of CD34 has remained remarkably elusive. This is probably because: (1) it is subject to a range of tissue-specific post-transcriptional and post-translational modifications that are expected to alter its function dramatically; (2) the simple interpretation of CD34 gain- and loss-of-function experiments has been confounded by the overlapping expression of the two recently discovered CD34-related proteins podocalyxin and endoglycan; and (3) there has been a glaring lack of robust in vitro and in vivo functional assays that permit the structural and functional analysis of CD34 and its relatives. Here, we provide a brief review of the domain structure, genomic organization, and tissue distribution of the CD34 family. We also describe recent insights from gain- and loss-of-function experiments and improved assays, which are elucidating a fascinating role for these molecules in cell morphogenesis and migration.
近30年来，细胞表面蛋白CD34已被广泛用作一种标志物，以协助鉴定和分离造血干细胞（HSC）及其祖细胞，为骨髓移植做准备。此外，它越来越多地被用作一种标志物，以帮助鉴定其他组织特异性干细胞，包括肌肉卫星细胞和表皮前体细胞。然而，尽管CD34作为一种干细胞标志物很有用，但它的功能仍然非常难以捉摸。这可能是因为：（1）它会经历一系列组织特异性的转录后和翻译后修饰，这些修饰预计会极大地改变其功能；（2）对CD34功能获得和功能丧失实验的简单解释因最近发现的两种与CD34相关的蛋白足突融合蛋白和内聚糖的重叠表达而变得复杂；（3）明显缺乏强大的体外和体内功能测定方法，无法对CD34及其相关蛋白进行结构和功能分析。在这里，我们简要回顾CD34家族的结构域结构、基因组组织和组织分布。我们还描述了功能获得和功能丧失实验以及改进的测定方法的最新见解，这些见解正在阐明这些分子在细胞形态发生和迁移中的迷人作用。
