Fig. 3. Misregulation of BMP signaling does not perturb specification of hematopoietic fate. Embryos were injected with RNA encoding caALK3 (near the VMZ) or tBR or Smad6 (near the DMZ) at the 4-cell stage. Expression of SCL was analyzed at neurula (St. 18) and tailbud (St. 32) stages by northern blot hybridization. The blot was stripped and reprobed for globin, and then EF-1 transcripts. The difference in SCL levels in tailbud stage embryos injected with Smad6 as opposed to tBR was not reproducible.