miR-144 is functionally active in vivo. (A,B) Expression of EGFP mRNAs and EGFP fluorescence in 16 and 24 hpf F1 embryos derived from Tg(zgata-1:EGFP) transgenic line 1 (A) or Tg(zgata-1:EGFP-2× PT) transgenic line 2 (B). Both EGFP mRNAs and green fluorescence expressed normally in the P-LPM of 16 hpf but became undetectable in the ICM of 24 hpf embryos from Tg(zgata-1:EGFP-2× PT) transgenic line. (Insets) Amplified views of fluorescent ICM. Arrowhead indicates nonspecific EGFP expression in the dorsal neurons. (C,D) Rescue of both EGFP mRNAs and protein fluorescence by microinjection of miR-144 LNA (C), but not its 5-bp mismatch control (D), into 1 cell–stage F1 embryos from Tg(zgata-1:EGFP-2× PT) transgenic line 2.