p28 dynein light chains and ciliary motility in Tetrahymena thermophila.

Dynein light chains are required for the assembly of axonemal dyneins into cilia and flagella. Most organisms express a single p28 dynein light chain and four to nine one-headed inner arm dynein heavy chains. In contrast, Tetrahymena encodes three p28 dynein light chain genes (p28A, p28B, and p28C) and 18 one-headed inner arm dynein heavy chains. In this article it is shown that mutations in p28A and p28B affected both beat frequency and waveform of cilia, while mutations in p28C affected only ciliary beat frequency. A similar set of dynein heavy chains were affected in both p28AKO and p28BKO, but a distinct set of heavy chains was affected in p28CKO. The results suggested that the p28s have non-redundant functions in Tetrahymena and that p28C was associated with a different set of dynein heavy chains than were p28A and p28B.