The outer dynein arm-docking complex: composition and characterization of a subunit (oda1) necessary for outer arm assembly.
To learn more about how dyneins are targeted to specific sites in the flagellum, we have investigated a factor necessary for binding of outer arm dynein to the axonemal microtubules of Chlamydomonas. This factor, termed the outer dynein arm-docking complex (ODA-DC), previously was shown to be missing from axonemes of the outer dynein armless mutants oda1 and oda3. We have now partially purified the ODA-DC, determined that it contains equimolar amounts of M(r) approximately 105,000 and approximately 70,000 proteins plus a third protein of M(r) approximately 25,000, and found that it is associated with the isolated outer arm in a 1:1 molar ratio. We have cloned a full-length cDNA encoding the M(r) approximately 70,000 protein; the sequence predicts a 62.5-kDa protein with potential homologs in higher ciliated organisms, including humans. Sequencing of corresponding cDNA from strain oda1 revealed it has a mutation resulting in a stop codon just downstream of the initiator ATG; thus, it is unable to make the full-length M(r) approximately 70,000 protein. These results demonstrate that the ODA1 gene encodes the M(r) approximately 70,000 protein, and that the protein is essential for assembly of the ODA-DC and the outer dynein arm onto the doublet microtubule.
Takada
Saeko
S
Department of Cell Biology, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA.
Wilkerson
Curtis G
CG
Wakabayashi
Ken-ichi
K
Kamiya
Ritsu
R
Witman
George B
GB
D020418:Algal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002696:Chlamydomonas / Q000166:cytology* / Q000378:metabolism; D004398:Dyneins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D005407:Flagella / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D046911:Macromolecular Substances; D008958:Models, Molecular; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010455:Peptides / Q000378:metabolism; D017433:Protein Structure, Secondary; D021122:Protein Subunits; D015800:Protozoan Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment
D020418:Algal Proteins; D046911:Macromolecular Substances; D010455:Peptides; D021122:Protein Subunits; D015800:Protozoan Proteins; D004398:Dyneins