Regulation of the expression of annexin VIII in acute promyelocytic leukemia.
Regulation of the expression of annexin VIII in acute promyelocytic leukemia.
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DOI：
10.1182/blood.v84.1.279.bloodjournal841279
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发表时间：
1994-07
期刊：
影响因子：
20.3
通讯作者：
A. Sarkar;P. Yang;Y. Fan;Z. Mu;R. Hauptmann;G. Adolf;S. Stass;K. Chang
中科院分区：
文献类型：
--
作者：
A. Sarkar;P. Yang;Y. Fan;Z. Mu;R. Hauptmann;G. Adolf;S. Stass;K. Chang
膜联蛋白VIII是一种钙依赖性磷脂结合蛋白，先前基于体外研究确定为血液抗凝剂。然而，膜联蛋白VIII的生理功能仍然未知。在急性早幼粒细胞白血病（APL）中，膜联蛋白VIII基因高度表达，但其表达在其他急性白血病的原始细胞中检测不到。在目前的调查中，我们表明，使用APL衍生的NB 4细胞系，膜联蛋白VIII基因的表达在转录水平上的全反式维甲酸（ATRA）诱导分化过程中进行调节。膜联蛋白VIII mRNA的半衰期为约5至6小时，如通过使用放线菌素D作为转录抑制剂所测定的。NB 4细胞和APL样品中膜联蛋白VIII蛋白的表达分析显示，主要的36-kD蛋白和弱的72-kD蛋白的一致表达。ATRA诱导分化后的NB 4细胞，膜联蛋白VIII蛋白水平逐渐降低，但可检测的水平持续，即使在4天的诱导。由于膜联蛋白VIII mRNA在ATRA诱导48小时后变得不可检测，因此该结果表明膜联蛋白VIII是相对稳定的蛋白质。进行了多组织北方印迹分析，我们发现膜联蛋白VIII在胎盘和肺中正常表达。免疫荧光染色和亚细胞分级法测定膜联蛋白VIII蛋白的细胞定位。这些结果表明，膜联蛋白VIII主要定位于质膜。膜联蛋白VIII既不是细胞外蛋白，也不与细胞表面相关，这表明它在体内血液凝固中不起作用。膜联蛋白VIII的质膜定位及其作为磷脂酶抑制剂的性质表明，它可能在APL细胞的信号转导途径中发挥作用。
Annexin VIII is a calcium-dependent phospholipid-binding protein previously identified as a blood anticoagulant based on in vitro studies. However, the physiologic function of annexin VIII remains unknown. In acute promyelocytic leukemia (APL) the annexin VIII gene is highly expressed, but its expression is undetectable in the blasts of other acute leukemias. In the present investigation, we showed using the APL-derived NB4 cell line that expression of the annexin VIII gene is regulated at the transcription level during induced differentiation by all-trans retinoic acid (ATRA). The half-life of the annexin VIII mRNA is about 5 to 6 hours, as determined by using actinomycin D as a transcription inhibitor. Analysis of the expression of annexin VIII protein in NB4 cells and in APL samples showed a consistent expression of a predominant 36-kD protein and a weak 72-kD protein. After ATRA-induced differentiation of NB4 cells, the annexin VIII protein level reduced gradually, but a detectable level persisted even after 4 days of induction. Because annexin VIII mRNA becomes undetectable after 48 hours of ATRA induction, this result indicates that annexin VIII is a relatively stable protein. A multiple tissue Northern blot analysis was performed, and we found that annexin VIII is normally expressed in the placenta and the lung. Cellular localization of the annexin VIII protein was determined by immunofluorescence staining and subcellular fractionation. These results indicated that annexin VIII is predominantly localized to the plasma membrane. The annexin VIII is neither an extracellular protein nor associated with the cell surface suggesting that it does not play a role in blood coagulation in vivo. The plasma membrane localization and its property as a phospholipase inhibitor suggests that annexin VIII may have a role in the signal transduction pathway in the APL cells.