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The 78,000 M(r) intermediate chain of chlamydomonas outer arm dynein is a WD-repeat protein required for arm assembly


Wilkerson, CG and King, SM and Koutoulis, A and Pazour, GJ and Witman, GB, The 78,000 M(r) intermediate chain of chlamydomonas outer arm dynein is a WD-repeat protein required for arm assembly, Journal of Cell Biology, 129, (1) pp. 169-178. ISSN 0021-9525 (1995) [Refereed Article]


Copyright Statement

Copyright 1995 by The Rockefeller University Press.

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DOI: doi:10.1083/jcb.129.1.169


We have isolated and sequenced a full-length cDNA clone encoding the 78,000 M(r) intermediate chain (IC78) of the Chlamydomonas outer arm dynein. This protein previously was shown to be located at the base of the solubilized dynein particle and to interact with alpha tubulin in situ, suggesting that it may be involved in binding the outer arm to the doublet microtubule. The sequence predicts a polypeptide of 683 amino acids having a mass of 76.5 kD. Sequence comparison indicates that IC78 is homologous to the 69,000 M(r) intermediate chain (IC69) of Chlamydomonas outer arm dynein and to the 74,000 M(r) intermediate chain (IC74) of cytoplasmic dynein. The similarity between the chains is greatest in their COOH-terminal halves; the NH2-terminal halves are highly divergent. The COOH-terminal half of IC78 contains six short imperfect repeats, termed WD repeats, that are thought to be involved in protein-protein interactions. Although not previously reported, these repeated elements also are present in IC69 and IC74. Using the IC78 cDNA as a probe, we screened a group of slow-swimming insertional mutants and identified one which has a large insertion in the IC78 gene and seven in which the IC78 gene is completely deleted. Electron microscopy of three of these IC78 mutants revealed that each is missing the outer arm, indicating that IC78 is essential for arm assembly or attachment to the outer doublet. Restriction fragment length polymorphism mapping places the IC78 gene on the left arm of chromosome XII/XIII, at or near the mutation oda9 which also causes loss of the outer arm. Mutants with defects in the IC78 gene do not complement the oda9 mutation in stable diploids, strongly suggesting that ODA9 is the structural gene for IC78

Item Details

Item Type:Refereed Article
Research Division:Biological Sciences
Research Group:Plant biology
Research Field:Plant cell and molecular biology
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the biological sciences
UTAS Author:Koutoulis, A (Professor Anthony Koutoulis)
ID Code:70900
Year Published:1995
Web of Science® Times Cited:140
Deposited By:Research Division
Deposited On:2011-07-05
Last Modified:2011-07-07
Downloads:338 View Download Statistics

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