Worm Breeder's Gazette 11(4): 76

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.

C. elegans Lectin-Binding Mutants

Chris Link, Michael Silverman, Moira Breen and Kathleen Watt

We have previously described a screen to identify mutants that show 
ectopic surface binding of lectins, and have now characterized 45 such 
mutants (See WBG v10 #3, p102).  This collection of mutants contains 
27 alleles of srf-2 I, 1 allele of srf-3 IV, 8 alleles of srf-4 V, 6 
alleles of srf-5 X, 2 alleles of srf(dv4) V and 1 allele of srf(dv38) V.
(The srf-2 and srf-3 genes have previously been identified by Sam 
Politz in screens using stage-specific anti-cuticle sera.) These 
mutations are all recessive and fall into two phenotypic classes: 
lectin binding mutants that are otherwise wild-type (srf:2,3,5) and 
lectin-binding mutants that are also male abnormal and uncoordinated (
srf-4, (dv4),(dv38) ).  srf-4 mutants are also dauer-defective and, 
surprisingly, show semi-dominant enhancement of dominant lin-12 
These observations raise three general questions: 1) Why do these 
mutants bind lectins? 2) How are the otherwise wild-type mutants 
different from the pleiotropic mutants? 3) Why do we care? In regard 
to the first question, these mutants presumably have altered cuticles, 
and most likely are missing some surface proteins that mask (normally 
inaccessible) surface glycoproteins.  In regard to the second question,
our best guess is that srf-2,3,5 defects are restricted to the 
cuticle, while the srf-4 class affects other tissues.  We care because 
we suspect that srf-4 is involved in some basic process (e.g., 
secretion of extracellular proteins or protein glycosylation) that is 
important in both male tail morphogenesis and lin-12 function.
We are addressing the above questions by purifying cuticles from 
these mutants and comparing their protein and glycoprotein profiles.  
We are particularly intrigued by the prospect of identifying 
glycosylation mutants, either as srf-4 like mutants, or by using our 
lectin-binding mutants in new screens .