CELLULAR POLARITY IN CILIATES - PERSISTENCE OF GLOBAL POLARITY IN A DISORGANIZED MUTANT OF TETRAHYMENA-THERMOPHILA THAT DISRUPTS CYTOSKELETAL ORGANIZATION

Much of the cell surface on the ciliate Tetrahymena thermophila is cov ered by a polarized lattice of cytoskeletal structures that are associ ated with basal bodies of the ciliary rows. Unique structural landmark s, including an oral apparatus and contractile vacuole pores, develop before cell division in localized domains located, respectively, poste rior and anterior to the transverse fission zone. All of these structu res can be visualized by specific monoclonal antibodies. A single-locu s recessive mutation, disorganized-ii (disA), primarily affects the st riated rootlets of the ciliary-row basal bodies and brings about a sev ere disorganization in the positioning and orientation of these basal bodies and associated cytoskeletal elements. Nonetheless, the new oral apparatus, contractile vacuole pores, and other unique structures app eared at or near their normal sites along the anteroposterior axis of disA cells, indicating that the positioning of these localized structu res is not dependent on the integrity of the ciliary rows. Abnormaliti es were present in the details of construction of some of the localize d structures and in aspects of cell shape that may be influenced by th ese details. In the main, however, analysis of disA mutant cells indic ates that intracellular domains near the cell poles develop independen tly of the vectorial polarity of the ciliary rows. (C) 1995 Academic P ress, Inc.