Figure 8

The collagen glycine repeat mutation G552D causes abnormal distribution of perlecan and Col4a2/Viking. Live fluorescent images of stage 17 embryos carrying GFP protein trap insertions trol^ZCL1973 or vkg^G454 to analyze the distribution of perlecan (A-F) or Vkg/Col4a2 (G-I), respectively. The org-1-SM-RFP reporter gene drives cytoplasmic RFP expression in org-1-positive somatic muscles as in Figure 1. Other reporter genes originally present in the newly isolated EMS mutants were removed by recombination. (A) Control showing normal perlecan distribution in and around the dorsal vessel (dv), in basement membranes of other organs (brain (br), gonad (go), lymph gland (lg), Malpighian tubules (mt)) and at dorsal body wall muscle attachment sites (mas, only partially in focus). (B) Homozygous LanB1^S0733 with similar perlecan distribution, except for reduced levels and discontinuous lining at the dorsal vessel. (C-F) In Cg25C mutant embryos perlecan is only partially detectable in a faint BM-like layer in the dorsal vessel and barely detectable in other BMs. Diffuse GFP-perlecan signals are detectable in dorsal and lateral areas of the embryos, some of which overlap with positions of PCs and AMs (arrows). Bright accumulations of GFP-perlecan appear in scattered hemocytes (hc) of homozygous Cg25C^S3064(C), Cg25C^DTS-L3(D) and to a lesser extent in hemizygous Cg25C^DTS-L3/Df(2L)Exel7022 (E) and type IV collagen null mutants (Df(2L)Exel7022, F). (G, H) Normal GFP-Vkg distribution in a heterozygous vkg^G454/+ control embryo (G) and a vkg^G454/LanB1^S0733 trans-heterozygote (H). Moderate levels are also observed in hemocytes (hc). (I) Trans-heterozygous vkg^G454/Cg25C^S3064 embryo in which GFP-Vkg is detectable around the dorsal vessel. Presence of Vkg in BMs is partially obscured by high-level accumulation in hemocytes and in the fat body (fb).