Transient missexpression of Id2, Id3, Foxc2 or Snail1 is sufficient to promote vascular at the expense of myotomal fates. (A) pBI-TRE-EGFP and pRev-Tet-off were co-electroporated into E2 avian somites targeting the presumptive lateral DM. Doxycyclin was administered 20 hours post-treatment and embryos were re-incubated for 24 hours. GFP + cells were found primarily in the myotome (M), co-expressing SMA/Desmin. A smaller fraction was found in the sclerotome and in blood vessel walls as SM cells (arrow) (N = 26). Transient over-expression of Id2 (B-B”, N = 19), Foxc2 (D-D”, N = 12) or Snail1 (E-E”, N = 7) or constant expression of Id3 (C-C”, N = 3) promoted an increase of cells within the sclerotome as well as SM (arrows and see also Additional file 4: Figure S4A). Endothelial cells were visualized with the Qh1 antibody (blue). (F) Quantifications (mean ± SEM). Distribution of GFP + cells in various locations as a percentage of total GFP + cells. *P ≤0.05; **P ≤0.01. Bar: (A-E) 100 μm; (B’, E’) 25 μm; (C’) 18 μm; (D’) 30 μm. CV, cardinal vein; Des, desmin; E, embryonic day; Scl, sclerotome; SEM, standard error of the mean; SMA, smooth muscle actin.