Worm Breeder's Gazette 2(2): 29

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.

An Internal Deletion Mutant of a Myosin Heavy Chain in C. elegans

A.R. MacLeod, R.H. Waterston, S. Brenner

E675, an allele of unc-54 has been known to possess a myosin heavy 
chain of 200 Kd in addition to the normal 210 Kd component.  Cleavage 
of the wild type heavy chains at cysteinyl residues by cyanylation 
gives rise to a prominent doublet of 150 Kd and 140 Kd.  In the mutant 
E675, the molecular weight of each component of the doublet is reduced 
equally by 10 Kd, indicating that the doublet arises by partial 
cleavage of a single polypeptide chain which is the product of the unc-
54 gene.  The use of 14C-cyanide during the cleavage reaction allows 
specific labelling of the N-termini of these cyanylation fragments.  
Limited cyanogen bromide cleavage of the labelled cyanylation 
fragments followed by gel electrophoresis and autoradiography of the 
partial digestion products shows that a large peptide of 40 Kd can be 
removed from the C-terminus of E675 cyanylation fragments without 
removing the peptide containing the e675 defect.  Furthermore e675 
causes the deletion of a methionine residue located 46 Kd from the C-
terminus of the N2 molecule.  Thus e675 appears to be a deletion of 10 
Kd within the 18 Kd limits from 38 Kd to 56 Kd of the C-terminus of 
the wild type molecule.