GENE EXPRESSION DURING OSTEOCLAST DIFFERENTIATION

破骨细胞是一种独特的细胞， 它与粒细胞和单核细胞谱系的细胞共享。当 激活后，它会变得两极化，形成一个皱褶的边界，并导致释放 骨矿物质和骨基质的蛋白水解降解。的目标 该项目旨在阐明在特定基因表达的变化， 骨溶解和前体分化期间。我们计划 量化两类特定基因表达的变化：a） 那些与骨质溶解直接相关的酶（如碳酸酐酶II， 溶酶体蛋白酶组织蛋白酶0，皱褶边缘质子泵，和 超氧化物歧化酶）和B）这些对调节性 因子如降钙素，维生素A，佛波醇肉豆蔻酸酯醋酸酯，1，25 二羟维生素D-3和肿瘤坏死因子。我们还将计划 确定这些基因产物的功能重要性， 培养的禽类破骨细胞的表型。会来做这项工作 引入表达有义或反义RNA的DNA构建体， 从而提高或降低特定细胞标记蛋白的水平 独立于细胞的激素调节。 这些研究将使用两个模型系统。人早幼粒 白血病细胞系HL-60与早期前体细胞具有共同的表型特征 破骨细胞谱系中的细胞。该细胞系将用作 早期破骨细胞祖细胞的代表。作为成熟的典范 破骨细胞，我们将使用分离的鸡破骨细胞。这些细胞不像 哺乳动物破骨细胞，有足够的数量， 分子生物学技术的应用。

The osteoclast is a unique cell which arises from a hematopoietic precursor it shares with cells of the granulocyte and monocyte lineages. When activated, it becomes polarized, forms a ruffled border and causes release of bone mineral and proteolytic degradation of the bone matrix. The goal of this project is to elucidate changes in expression of specific genes during osteolysis and during differentiation of the precursors. We plan to quantify changes in the expression of two classes of specific genes: a) those directly associated with osteolysis (such as carbonic anhydrase II, the lysosomal protease cathepsin 0, the ruffled border proton pump, and superoxide dismutase) and b) hormonal responses of these to regulatory factors such as calcitonin, vitamin A, phorbol myristate acetate, 1,25 dihydroxyvitamin D-3 and tumor necrosis factor. We will also plan to determine the functional importance of these gene products by manipulating the phenotype of cultured avian osteoclasts. This will be done by the introduction of DNA constructs which express sense or antisense RNA, thereby raising or lowering the levels of specific cellular marker proteins independent of hormonal regulation of the cells. Two model systems will be used for these studies. The human promyelocytic leukemic cell line HL-60 shares phenotypic features with early precursor cells in the osteoclast lineage. This cell line will be used as a representative of an early osteoclast progenitor. As a model for mature osteoclasts, we will use isolated chicken osteoclasts. These cells, unlike mammalian osteoclasts, are available in sufficient quantities to allow application of the techniques of molecular biology.