The dynein heavy chain gene family in Tetrahymena thermophila

The dynein ATPases are a family of motor enzymes that drive microtubule sli ding in cilia and flagella and contribute to microtubule-based transport in side cells. The multi-dynein hypothesis makes two predictions: 1) Axonemes contain multiple dynein heavy chain (DHC) isoforms, each encoded by a diffe rent gene; 2) Each isoform performs a specific role in ciliary beating. We used PCR-based techniques to clone thirteen different DHC sequences from Te trahymena genomic DNA. All thirteen genes appeared to be expressed in growi ng cells. Comparisons of the deduced amino acid sequences of the thirteen D HCs with other known DHCs suggested that we have cloned three outer arm DHC s, two cytoplasmic DHCs, and eight inner arm DHCs.