Coordinated regulation of Hox UTRs by the SPT-miRNAs. (A) Schematic diagrams of predicted target sites of SPT-miRNAs on Hoxb6, Hoxa4, and Hoxd13. Repression of luciferase reporters bearing UTRs from Hoxb6 (B), Hoxa4 (C), or Hoxd13 (D) by the SPT-miRNAs and corresponding seed mutant controls (sm) (n = 3, mean ± SD, two-tailed, type 2, Student t-test, compared to the control vector, N.S. for p > 0.05). (E) Model of SPT-miRNA regulation of Hox genes during the stem to progenitor transition and corresponding changes in self-renewal and proliferation potentials.