Muscle attachment sites are disrupted in pat-9 mutants. N2 (A, B, C, D and E) and pat-9(st558) (A’, B’, C’ D’ and E’) embryos were stained with monoclonal antibodies to UNC-52/perlecan (A and A’), PAT-3/beta-integrin (B and B’), PAT-4/ILK (C and C’), DEB-1/vinculin (D and D’) and MYO-3/MHC-A (E and E’). All five proteins are expressed in pat-9(st558) embryos indicating PAT-9 does not regulate these genes. Arrows show the structures stained by each antibody. All the animals were co-stained with monoclonal antibody MH27 to visualize the hypodermal cell junctions, enabling the identification of the orientation and age of the embryos. Bar = 10 μm.3rd exon.