Fig. 2

Fig. 2 Loss of Etsrp function results in the failure of fibronectin 1-expressing endocardial precursors to migrate towards the midline. (A-D) Fibronectin 1 (fn1) expression (arrowheads) in the presumptive endocardial precursors is slightly expanded rostrally in etsrp^y11–/– mutants at the 8- to 12-somite stages, as analyzed by in situ hybridization. (E-H) fn1-expressing endocardial precursors (arrowheads) migrate to the midline in wild-type sibling embryos, while they remain localized bilaterally in etsrp^y11–/– mutants at the 14- to 16-somite stages. (I-P) fn1 expression largely overlaps with etsrp:GFP expression in the presumptive endocardial precursor cells (white arrowheads) in uninjected control embryos and etsrp morphants. Maximum projection image of etsrp:GFP immunofluorescence (I,J) and fn1 in situ hybridization staining (K,L). Merged images of bright-field (BF) and GFP channels (M-P). There is slight expansion of fn1 and etsrp:GFP staining in etsrp morphants. O,P are higher magnification views of the insets in M,N, respectively. (A-P) Ventral views of flat-mounted embryos, anterior is upwards.