Studies of Marginal Band Formation and Function in Erythrocytes

点击翻译按钮获取中文摘要

Continuous circumferential bundles of microtubules, known as marginal bands (MBs), are prominent cytoskeletal components in all non- mammalian vertebrate erythrocytes and a wide range of other blood cell types. In previous work the investigator has shown that MBs of mature cells can maintain erythrocyte shape against deformation by external forces. However, the function of the MB during erythrocyte morphogenesis from sphere to flattened ellipse remains unknown. In the proposed work the principal investigator will test a working hypothesis for the relationship between the state of MB assembly nd stage of cellular morphogenesis, in which pointed cells constitute intermediate stages. The tests include recording of the precise morphological sequence by phase contrast/video microscopy, immunofluorescence localization of microtubules and centriole-containing organizing centers, and analysis of microtubule polarity at an early critical stage. A related study on chick bone marrow erythroblasts in culture will determine whether cells of pointed morphology are a universal intermediate stage. The proposal also includes continued studies on the structure and composition of marginal bands isolated from dogfish erythrocytes by improved procedures, and of marginal band proteins obtained by selective solubilization from cytoskeletons. These studies will enhance our understanding of the mechanisms involved in the biogenesis and function of microtubule arrays. They will also provide insight into cytoskeletal function during cell differentiation, a significant issue in cell biology research.