TEKTINS AS STRUCTURAL DETERMINANTS IN BASAL BODIES

Tektins, present as three equimolar 47-55 kDa protein components, form highly insoluble protofilaments that are integral to the junctional r egion of outer doublet microtubules in cilia and flagella. To identify and quantify tektins in other compound microtubules such as centriole s or basal bodies, a rabbit antiserum was raised against tektin filame nts isolated from Spisula solidissima (surf clam) sperm flagellar oute r doublets and affinity-purified with nitrocellulose blot strips of te ktins resolved by SDS- or SDS-urea-PAGE. These antibodies recognized a nalogous tektins in axonemes of organisms ranging from ctenophores to higher vertebrates. Quantitative immunoblotting established that outer doublet tektins occur in a 1:17 weight ratio to tubulin. Cilia and ba sal apparatuses were prepared from scallop gill epithelial cells; cili a and deciliated cells were prepared from rabbit trachea. Tektins were detected by immunoblotting in basal body-enriched preparations while tektins were localized to individual basal bodies by immunofluorescenc e. Supported by greater fluorescence in basal bodies than in adjacent axonemes in tracheal cells, analysis of basal apparatuses demonstrated both a proportionately greater ratio of tektin to tubulin (similar to 1:13) and two distinct solubility classes of tektins, consistent with tektins comprising the B-C junction of triplets in addition to the A- B junction as in doublets. Cell Motil. Cytoskeleton 40:379-392, 1998. (C) 1998 Wiley-Liss,Inc.