Dissociation of annulate lamellae in P3J, a Burkitt's lymphoma cell line

The induced dissociation of stacks of annulate lamellae in multinuclear cells of P3J, a Burkitt's lymphoma cell line, is described. The multinuclear cells form as a portion (15-25%) of the population when growth of P3J is prevented by high concentrations (100-200 micrograms/ml) of alpha-difluoromethylornithine (DFMO), an inhibitor of polyamine biosynthesis. All cells in the population form stacks of annulate lamellae when incubated in DFMO and when the action of DFMO is reversed by the addition of putrescine, the annulate lamellae disappear. However, unlike the typical (uninucleate) cells in the population, the multinucleate ones do not divide following the addition of putrescine. During dissociation, the annulate lamellae fragment into small segments of cisternae and vesicles of various sizes. Although some of the electron-dense pore material is dispersed in the cytoplasm, much is retained with the vesicular elements that form.