Figure 4. FRG-1 associates with body-wall muscle cell dense bodies, adjacent to PAT-3, and colocalizes with ALP-1. (A-F) Adult animals co-immunostained for FRG-1 (A,D, green) and PAT-3 (B,E, red) show FRG-1 present at all body-wall muscle dense bodies (C, arrowheads), whereas it is absent from M-lines (C, arrows). FRG-1 and PAT-3 show adjacent, partially overlapping signals at dense bodies when merged (C,C', arrowheads). (D-F) Confocal images of dense body immunostaining. (G-I) Double transgenic animals for Pmyo-3::
frg-1::yfp and Pmyo-3::
alp-1alpha::cfp show that expression patterns for FRG-1 (G) and ALP-1 (H) are precisely colocalized in the image merge (I and I'). (J-L) Mutant C. elegans strain containing a homozygous partial deletion for
atn-1 was co-immunostained for FRG-1 (J, green) and PAT-3 (K, red), showing disrupted FRG-1 localization (L). (M) Model depicting FRG-1 localization in dense bodies with the analogous vertebrate components (based on Moerman and Williams, 2006; Fluck et al., 2002). Scale bars: 20 μm. DGC, dystrophin-glycoprotein complex; IRC, integrin receptor complex.