Figure 7

Figure 7

Mutant ΔI258D259Comp expression in vertebral column and muscle of zebrafish. Comp immunostainings were performed on paraffin-embedded tissue sections (A-D) from 5-month-old wild type (wt) (A, C) (n=4) and homozygous ΔI258D259Comp (B, D) (n=4) zebrafish by using affinity-purified rabbit (A-D) and guinea pig (E, F) antisera specific for zebrafish Comp, alkaline phosphatase-conjugated streptavidin and Fast Red staining (A-D) and secondary Alexa 488 conjugated antibodies (E, F). (A) In the vertebral column of 5-month-old wt zebrafish, Comp is found in the fibrocartilaginous tissue at the base of the intervertebral discs (ivd) (arrows) and lining the inner part of the bones (b) (arrowheads), (vt, vacuolated tissue). (B) In mutant ΔI258D259Comp zebrafish this expression is nearly completely lacking. However, the architecture of the vertebral column is not altered. (C) In adult wild type zebrafish Comp is still uniformly found in myosepta (m). (D) Also in adult mutant ΔI258D259Comp zebrafish Comp is found in myosepta (m) but with an irregular patchy distribution (arrowheads). (E, F) This is similar in 72 hpf zebrafish where Comp is strongly and uniformly found in myosepta (m) of wt (E) and in irregular patches (arrowheads) interrupted by a much weaker uniform staining (arrows) in ΔI258D259Comp zebrafish as shown by whole mount immunofluorescence staining using an affinity-purified guinea pig antiserum specific for zebrafish Comp (E, F) (n=100), see also Figure 6C. Bars: 100 µm in (A-D) and 10 µm in (E, F).