Globin transcript levels are dependent on STAT5 repressor activity. Embryos were injected with a control morpholino or the STAT5 morpholino (STAT5 MO) and, in addition, 1 ng RNA encoding STAT5-EnR, or RNA encoding lacZ as a control. Embryos were harvested at stage 24-25 and RNA processed for quantitative RT-PCR assays. Each independent sample consisted of a pool of 50 embryos. The median of each sample was normalized to its respective ODC control, and the median average from 4 independent experiments was graphed as fold change in RNA expression. Error bars indicate standard error of the mean. The asterisk indicates that the change in α-globin transcript levels comparing control injected and STAT5 MO injected (first and second samples) is statistically significant (P < .001). The double asterisk indicates that the rescue with STAT5-EnR RNA compared to MO co-injected with lacZ RNA (second and third samples) is statistically significant (P < .03).