Altered expression of annexin II in human B-cell lymphoma cell lines
Altered expression of annexin II in human B-cell lymphoma cell lines
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DOI：
10.1016/0167-4889(96)00103-6
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发表时间：
1996-10-11
影响因子：
5.1
通讯作者：
Vishwanatha, JK
中科院分区：
文献类型：
--
作者：
Chiang, YP;Davis, RG;Vishwanatha, JK
膜联蛋白II是一种生长调节基因，其表达在各种人类癌症中显著增加。我们研究了膜联蛋白II在11个人B细胞淋巴瘤细胞系和正常B细胞中的表达。在这些细胞系中观察到膜联蛋白II水平的广泛变化。在5个细胞系中观察到膜联蛋白II过表达，而在Raji、OMA-BL-I和REH细胞系中观察到显著降低的表达。Raji和OMA-BL-I细胞系中膜联蛋白II基因、mRNA和蛋白的分析表明，膜联蛋白II基因未改变，并且在这些细胞中产生低水平的膜联蛋白II转录物。下调膜联蛋白II的表达是在转录水平上，并没有重新表达膜联蛋白II的细胞与去甲基化剂处理后观察到。因此，膜联蛋白II基因的甲基化似乎不是膜联蛋白II下调的原因。在Raji和OMA-BL-I细胞中检测到膜联蛋白II的缓慢迁移改变形式，其用抗鸡膜联蛋白II抗血清检测到，但用抗人膜联蛋白II抗血清检测不到。缓慢迁移的膜联蛋白II物种被认为是敏感的小牛肠碱性磷酸酶的去磷酸化，导致在SDS-聚丙烯酰胺凝胶上的蛋白质的大小减少。在人K562和HeLa细胞的核提取物中也观察到磷酸化的膜联蛋白II。因此，Raji和OMA-BL-I细胞仅产生膜联蛋白II的磷酸化形式，而磷酸化膜联蛋白LI可能对细胞存活和增殖很重要。
Annexin II is a growth-regulated gene, whose expression is significantly increased in various human cancers. We examined annexin II expression in 11 human B-cell lymphoma cell lines and in normal B-cells. Wide variation was observed in the levels of annexin II in these cell lines. Annexin II overexpression was observed in 5 cell lines, while significantly reduced expression was observed in Raji, OMA-BL-I and REH cell lines. Analysis of the annexin II gene, mRNA and protein in Raji and OMA-BL-I cell lines indicated that annexin II gene was unaltered and that a low level of annexin II transcripts are produced in these cells. Down-regulation of annexin II expression was at the transcriptional level, and no reexpression of annexin II was observed after treatment of cells with demethylating agents. Thus methylation of the annexin II gene does not appear to be responsible for annexin II down-regulation. A slow migrating altered form of annexin II was detected in Raji and OMA-BL-I cells, which was detected with the anti-chicken annexin II antiserum, but not with the anti-human annexin II antiserum. The slow migrating annexin II species was found to be sensitive to dephosphorylation by calf intestinal alkaline phosphatase, resulting in reduction of the size of the protein on SDS-polyacrylamide gels. The phosphorylated annexin II was also observed in nuclear extracts of human K562 and HeLa cells. Thus, Raji and OMA-BL-I cells exclusively produce a phosphorylated form of annexin II, and phosphorylated annexin LI may be important for cell survival and proliferation.