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.
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.