Abstract
The microtubules of nucleated erythrocytes form an extraordinary structure: they are organized into a marginal band at the periphery of the cell. This unusual organelle, recurring in detail in each cell, provides an excellent opportunity to study the determinants of microtubule form. The marginal band was reformed, using detergent-extracted erythrocytes that were depleted of microtubules in vivo and phosphocellulose-purified tubulin from calf brain. Detergent-extracted cytoskeletons incubated under these conditions again have microtubules, and the pattern of these microtubules recapitulates several features of the intact marginal band. Most of the microtubules after regrowth are located in a band at the periphery of the cell, and curve to form an ellipse. The hypothesis that the specification of microtubule location and shape in these cells is governed by determinants that reside at the periphery of the cell is supported.