Nomura S, Wills A J, Edwards D R, Heath J K, Hogan B L
Laboratory of Molecular Embryology, National Institute for Medical Research, Mill Hill, London, United Kingdom.
J Cell Biol. 1988 Feb;106(2):441-50. doi: 10.1083/jcb.106.2.441.
2ar has been identified as a gene inducible by tumor promoters and growth factors in a variety of cultured mouse cell lines (Smith, J. H., and D. T. Denhardt. 1987. J. Cell. Biochem. 34:13-22). Sequence analysis shows that it codes for mouse osteopontin, an RGDS-containing, phosphorylated, sialic acid-rich Ca++-binding protein originally isolated from bone (Oldberg, A., A. Franzen, and D. Heinegard. 1986. Proc. Natl. Acad. Sci. USA. 83:8819-8823; Prince, C. W., T. Oosawa, W. T. Butler, M. Tomana, A. S. Brown, and R. E. Schrohenloer. 1987. J. Biol. Chem. 262:2900-3907.). In this paper we use Northern blot analysis and in situ hybridization to localize expression of 2ar during mouse embryogenesis. 2ar RNA is first detected in developing limb bones and calvaria at 14.5 d p.c., in a population of cells distinct from those expressing SPARC (osteonectin). High levels of 2ar expression are also seen in the bone marrow-derived granulated metrial gland cells of the deciduum and placenta, and in a number of epithelial tissues, including embryonic and postnatal kidney tubules, uterine epithelium and sensory epithelium of the embryonic ear. The temporal and spatial pattern of 2ar expression seen in vivo suggests that the protein plays a wider role than previously realized, in processes which are not confined to bone development.
2ar已被鉴定为在多种培养的小鼠细胞系中可被肿瘤启动子和生长因子诱导的基因（史密斯，J. H.，和D. T. 登哈特。1987年。《细胞生物化学杂志》34:13 - 22）。序列分析表明它编码小鼠骨桥蛋白，一种含RGDS、磷酸化、富含唾液酸的钙离子结合蛋白，最初从骨中分离得到（奥尔德伯格，A.，A. 弗兰岑，和D. 海内加德。1986年。《美国国家科学院院刊》83:8819 - 8823；普林斯，C. W.，T. 大泽，W. T. 巴特勒，M. 托马纳，A. S. 布朗，和R. E. 施罗亨勒。1987年。《生物化学杂志》262:2900 - 3907）。在本文中，我们使用Northern印迹分析和原位杂交来定位2ar在小鼠胚胎发育过程中的表达。2ar RNA首先在胚胎发育第14.5天的发育中的四肢骨骼和颅骨中被检测到，存在于与表达SPARC（骨连接素）的细胞不同的一群细胞中。在蜕膜和胎盘的骨髓来源的颗粒状子宫腺细胞以及一些上皮组织中也可见到高水平的2ar表达，包括胚胎和出生后的肾小管、子宫上皮以及胚胎耳的感觉上皮。在体内观察到的2ar表达的时间和空间模式表明，该蛋白在不限于骨骼发育的过程中发挥着比以前认识到的更广泛的作用。
