IONIC MECHANISMS IN THE REGULATION OF MITOSIS

我们将记录和调查变化在以下方面的作用 细胞内游离钙在有丝分裂中的作用 它们在控制细胞结构方面发挥作用。我们发现， 核膜上细胞内游离钙离子增加 有丝分裂过程中的分裂和后期的开始 海胆胚胎和细胞的快速卵裂期 组织培养中动物细胞的分裂。为了扩展这项工作，我们 将在对细胞进行视觉观察的同时 钙的测量是为了准确地定位 与结构性事件的关系，无论在时间上还是在两个方面- 细胞内游离钙分布的三维图像。我们 将试图在细胞核内阻止细胞周期的进展 包膜击穿和中后期转变 动物细胞通过控制钙从外部或通过 微量注射钙降低细胞内游离钙 缓冲区。我们对抗体的初步结果表明 钙/钙调蛋白依赖的蛋白激酶在正常进程中 通过核包层破裂。我们将把这些扩展到 包括中期-后期过渡的研究，并试图 以钙非依赖性形式重新启动两个点的有丝分裂 当有丝分裂被低钙抑制时这种酶的活性 缓冲区。

We will document and investigate the role of changes in intracellular free calcium during mitosis to determine what role they play in controlling cell structure. We have found that intracellular free calcium increases at nuclear envelope breakdown and at the onset of anaphase during mitosis both during the rapid cleavage stage of the sea urchin embryo and during cell division in animal cells in tissues culture. To extend this work we will make visual observations of the cell at the same time the calcium measurements are taken to pin-point the exact relationship to the structural events, both in time and in two- dimensional images of free calcium distribution in the cell. We will attempt to block progression of the cell cycle at nuclear envelope breakdown and at the metaphaseanaphase transition in animal cells by controlling calcium entry from outside or by lowering intracellular free calcium with microinjected calcium buffers. Our preliminary results with anti-bodies have implicated Ca2+/calmodulin-dependent protein kinase in normal progression through nuclear envelop breakdown. We will extend these these studies to include the meta-anaphase transition and try to reinitiate mitosis at both points with calcium-independent forms of this enzyme when mitoses has been arrested by low calcium buffers.