Worm Breeder's Gazette 8(3): 54

These abstracts should not be cited in bibliographies. Material contained herein should be treated as personal communication and should be cited as such only with the consent of the author.

Abnormal Assembly of Sensory Cilia

L. Perkins, J. Culotti

Figure 1

The amphid channel cilia are about 7.5 microns long.  Nine doublet-
microtubules extend for most of the length.  These microtubules are 
attached to the ciliary membrane by Y-links (a).  Near the base of the 
cilia, the doublet-microtubules are drawn together by a cylindrical 
structure, called the apical ring (b).  The Y-links are pulled inward 
and reveal their true shape.  A variable number of small singlet-
microtubules originate on the inner face of the ring.  Below the 
apical ring the Y-links are elaborated into transitional fibers which 
connect the doublet microtubules to the membrane (c).  There are no 
basal bodies.  In three mutants che-10(e1805), 8), 
and osm-5 (p813), all of the sensory cilia assemble abnormally.  The 
phenotypes are similar for all three mutants and, for simplicity, we 
describe the channel cilia only.  The proximal structures including 
the transitional fibers and the apical ring are present and 
essentially normal.  The central microtubules end with the ring 
however, and the outer doublets extend only a little further.  
Surprisingly, the bulk of the missing microtubules can be accounted 
for by doublet-microtubules than assemble ectopically behind the cilia 
(d).  These doublets are attached to the membrane by Y-links and 
allign longitudinally to make a cilia-like projection directed 
posteriorly in the sheath cell (e).  Like the normal cilia, these 
ectopic projections are topologically distal to the neuron/sheath 
junctions.  We suggest that the microtubules and their links self-
assemble and the wild type che-10,  
are needed to ensure that they assemble only on the correct template.  

[See Figure 1]

Figure 1