Paramyosin is a core structural component of thick filament in invertebrate muscle. In C. elegans , many paramyosin mutations are in the C-terminal region of the molecule;
e1215 (Q809R),
su228 (R837C),
su2000 (EH702D). Thus this region may play an important role in assembly by the interaction of charged residues. The paramyosin mutant
e1402 has hydrophobic substitution (L799F) in the C-terminal region. This mutation causes temperature sensitive Unc and embryonic lethal phenotypes, but the underlying molecular mechanisms are not well known. To study the relationship between paramyosin disassembly and embryonic lethality, we made transgenic animals with paramyosin GFP fusion proteins (PM-GFPs, GFP tagged at the N-terminal: GFP-PM or C-terminal: PM-GFP of paramyosin). Null mutation
e1214 animal was recovered its motility with GFP-PM, but not with PM-GFP. Recovered motility was proportion to fluorescent filament assembly of the transgenic animals. Quantities of paramyosin and PM-GFPs were also detected on Western analysis by using paramyosin and GFP antibodies. In transgenic animals of
unc-15 semidominant alleles (
e73,
e1215,
su228,
su2000 ), GFP-PM was a good marker for monitoring filament assembly. In temperature sensitive (
e1402 ) mutant, GFP-PM was also powerful to visualize the thick filament during development. Although over-produced PM-GFPs in the transgenic worm from N2 disrupted filament assembly and impaired locomotion of the worms, GFP-PM assembled same as that of native paramyosin and was a good marker to insight into the cause of the embryonic lethality. Our analyses, using PM-GFPs will allow to indicate how the embryonic lethality occurs due to disassembling of paramyosin.