The dynein heavy chain gene family in Tetrahymena thermophila

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