mta3 function is dependent on HDAC activity and other components of NuRD complex enhance primitive hematopoiesis. (A) Dependence of mta3 function on HDAC activity. Wild-type embryos or mta3 (350 pg)–injected embryos at 80 to 90 epiboly stages were incubated in Holtfreter solution (control) or in 0.2mM VPA (a deacetylase inhibitor) and fixed at the 10-somite or 14-somite stages for examining scl expression. Note that mta3 overexpression failed to restore scl expression in the presence of VPA, suggesting a requirement of HDAC activity for mta3 function. (B) scl and lmo2 expression in the posterior lateral mesoderm at the 10-somite stage was enhanced by overexpression of human HDAC1 (340 pg), MBD3 (500 pg), or MTA3 (500 pg). All embryos are shown in posterodorsal view.