Radial Spoke Defects Research Articles

Upper Respiratory Tract Ciliary Ultrastructural Pathology

Nasal and sinus ciliary ultrastructure was evaluated in 16 patients with various pathologies of the upper respiratory tract including sinusitis, nasal polyposis, purulent rhinitis, and rhinitis medicosa. Ultrastructural findings include absent dynein arms, central tubule disorientation, radial spoke defects, atypical microtubule patterns and ciliary membrane abnormalities. Examples of each condition are presented and the implications of these findings are discussed.

Oversized flagellar membrane protein in paralyzed mutants of Chlamydomonas reinhardrii.

A mutant strain of Chlamydomonas reinhardtii is shown to possess an oversized flagellar membrane protein. The mutant has paralyzed flagella, is temperature sensitive for flagellar assembly, and has an abnormal axonemal protein composition. All phenotypes appear to derive from a single Mendelian mutation, and genetic analysis suggests that the mutation, which call ts222, is in the gene pfl. Because pf1 mutants are known to have radial-spoke defects (Piperno et al., 1977, Proc. Natl. Acad. Sci. U. S. A. 74:1600-1604; and Witman et al., 1978, J. Cell Biol. 76:729-797), a relation as yet undefined appears to exist between radial-spoke and flagellar membrane biogenesis.

Cilia with Defective Radial Spokes

We studied the fine structure of respiratory-tract cilia in three siblings with chronic respiratory disease, comparing them with those from a patient with Kartagener's syndrome who had dynein-deficient cilia and with control patients who had chronic bronchitis or chronic sinusitis. Electron microscopy of the siblings revealed a new abnormality in the ciliary axoneme--namely, lack of the radial spokes. Their cilia showed an eccentric central pair of tubules but otherwise had a normal central sheath, outer-doublet microtubules, nexin links and dynein arms. The cilia were immotile. Mucociliary clearance was completely lacking in the three siblings and in the patient with Kartagener's syndrome, but was normal in their parents and unaffected siblings. Sperm from the male sibling showed identical structural abnormalities and were immotile. We consider the radial spoke defect to be the congenital anomaly responsible for dysfunction of the mucociliary clearance mechanism in these three patients and of the immotile sperm in one of the them. This defect is apparently another cause of the "immotilecilia syndrome."