Differentiation without mitosis in Dictyostelium discoideum.

Dictyoselium discoideum Ax-2 amoebae incubated in the presence of the microtubule inhibitor nocodazole, irreversibly lost their ability to multiply. Nocodazole-treated cells remained viable and RNA and protein synthesis continued for at least 48 h. When nocodazole-treated amoebae were allowed to develop on Millipore filters or on agar slides they differentiated with some delay when compared with controls. These results show that mitosis, naturally present during the developmental cycle of Dictyostelium discoideum Ax-2, is not indispensible for differentiation.