FIGURE 1.

Changes in miR expression following inhibition of FGF signaling. A, comparison of miR expression levels in RNA samples from control versus SU5402-treated primitive streak regions of embryos, determined by real-time PCR. All miRs detected in the primitive streak region of gastrula stage embryos (supplemental Table 1) were assessed for changes in expression levels. Only those miRs with a statistically significant change in abundance are shown. Statistical significance was determined using a non-paired t test. Inset shows ISH detection of miR-let-7b in control versus SU5402-treated embryos. miR-let-7b expression was increased throughout the embryo, particularly in the primitive streak and more anteriorly. Error bars indicate S.E. B, ISH analysis of miR expression HH stage 4 embryos. miR-let-7b staining in the primitive streak was variable, with some embryos showing robust streak staining (B), whereas others showed somewhat reduced expression in the streak itself (e.g. control embryo in A).