Worm Breeder's Gazette 3(2): 27a

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.

Title unknown.

Authors unknown.

We are studying the role of two myosins in body-wall muscle cells of 
the nematode, Caenorhabditis opulations of 
nematodes are synchronized, and the synthesis and accumulation of 
myosin heavy chains and total protein are followed through postmitotic 
larval development.  For both the wild-type N2 and the body-wall 
muscle-defective mutant E675, growth is exponential with time.  The 
mutant has a longer protein doubling time than wild-type.  Utilizing 
the electrophoretic polymorphism of the E675 myosin heavy chains, we 
show distinguishable classes of heavy chains accumulate differentially 
through development.  Immunochemical measurements comfirm a similar 
result in N2.  Total myosin heavy chain accumulation is also 
quantitatively similar for the two strains relative to total protein.  
Myosin heavy chain relative synthetic rates as determined by pulse-
labelling are constant throughout development and equivalent for two 
strains.  The final fraction of accumulated unc-54 to total heavy 
chains, about 0.63, equals the constant synthetic fraction, about 0.62.

Because myosin heavy chain accumulation and relative synthesis are 
equivalent, we conclude that the turnover of heavy chains is also 
similar in N2 and E675 despite the extensive structural and functional 
disruption within body-wall muscle cells of the latter strain.  Since 
the accumulated fraction of unc-54 myosin heavy chains plateaus at the 
constant synthetic fraction, myosin accumulation in the body-wall 
muscle cells may be attributed to a constant ratio of synthetic rates 
of the two body-wall myosin species.  We are currently investigating 
the mechanisms regulating this coordinate synthesis.