Bayna E M, Shaper J H, Shur B D
Department of Biochemistry and Molecular Biology, University of Texas, M. D. Anderson Hospital and Tumor Institute, Houston 77030.
Cell. 1988 Apr 8;53(1):145-57. doi: 10.1016/0092-8674(88)90496-5.
Cell surface beta-1,4 galactosyltransferase (GalTase) is shown to mediate intercellular adhesions between embryonal carcinoma (EC) cells and specifically during late morula compaction in the preimplantation mouse embryo. Monospecific anti-GalTase IgG raised against affinity-purified bovine beta-1,4 GalTase recognizes F9 EC cell GalTase as judged by immunoprecipitation and inhibition of GalTase activity, as well as by immunoprecipitation of a single 52 kd metabolically labeled membrane protein. Anti-GalTase IgG inhibits cell adhesions between EC cells, dissociates compacted mouse morulae, and inhibits blastocyst formation. Anti-GalTase IgG specifically inhibits cell adhesions during late morula compaction, coincident with a peak of surface GalTase activity as determined by direct enzyme assay. On EC cells, GalTase activity can be proteolytically released from intact cells, and is localized by indirect immunofluorescence to areas of intercellular contact, consistent with its proposed role in cell adhesion. Beta-1,4 GalTase is the first cell adhesion molecule identified that participates during late morula compaction, subsequent to uvomorulin function.
细胞表面β-1,4半乳糖基转移酶（GalTase）已被证明可介导胚胎癌细胞之间的细胞间黏附，特别是在植入前小鼠胚胎的晚期桑椹胚致密化过程中。通过免疫沉淀、GalTase活性抑制以及对单一52kd代谢标记膜蛋白的免疫沉淀判断，针对亲和纯化的牛β-1,4 GalTase产生的单特异性抗GalTase IgG可识别F9胚胎癌细胞GalTase。抗GalTase IgG抑制胚胎癌细胞之间的细胞黏附，使致密化的小鼠桑椹胚解离，并抑制囊胚形成。抗GalTase IgG在晚期桑椹胚致密化过程中特异性抑制细胞黏附，这与通过直接酶测定确定的表面GalTase活性峰值一致。在胚胎癌细胞上，GalTase活性可从完整细胞中被蛋白水解释放，并通过间接免疫荧光定位于细胞间接触区域，这与其在细胞黏附中的假定作用一致。β-1,4 GalTase是第一个被鉴定出在晚期桑椹胚致密化过程中发挥作用的细胞黏附分子，发生在uvomorulin功能之后。
