A membranous spindle envelope confines Megator and soluble tubulin during early mitosis. (A) Live S2 cells expressing mCherry–α-tubulin treated with DiO6C(3). (B) Live S2 cell expressing Megator-mCherry and GFP–α-tubulin in which the spindle envelope has been disrupted by laser microsurgery (arrowhead) after MT depolymerization with colchicine. (C and D) Live HeLa cells expressing mRFP–α-tubulin and histone H2B-GFP treated with DiOC6(3), with/without nocodazole as indicated. (E) Live HeLa cell expressing Tpr-GFP and mCherry–α-tubulin after nocodazole-induced MT depolymerization before NEB. Time is in minutes:seconds, relative to laser microsurgery (B) or NEB (D and E). Bars, 10 µm.