A screen was instigated to identify novel protein components of the 
Caenorhabditis elegans sarcomere. The subcellular localisation of full-length 
GFP fusion proteins was examined, in transgenic animals, for 62 essentially 
uncharacterized genes thought to be expressed within bodywall muscle cells. 
Three genes, T03G6.3, C46G7.2 and K04A8.6, were identified for further study. 
K04A8.6::GFP only displayed a regular sarcomeric distribution sporadically. 
However, C46G7.2::GFP localised to the centre of A-bands and dense bodies and 
T03G6.3::GFP localised in the I-band, of the bodywall muscle sarcomeres, 
consistently. This success with such a small screen suggests that there are 
further minor components of the C. elegans sarcomere yet to be discovered. 
Fluorescence Recovery After Photobleaching (FRAP) was applied to live transgenic 
individuals to assess the mobility of T03G6.3 and C46G7.2 and other well-known 
constituents of the sarcomere in vivo. Proteins associated with the thin 
filaments showed dynamic exchange whilst those associated with thick filaments 
appeared more static. This is the first demonstration that there are sarcomeric 
proteins in C. elegans muscle cells in dynamic exchange and that the rates of 
exchange in vivo correspond in general terms with observations in other 
experimental systems.