Knockdown of Elavl1a disrupts normal embryonic development. (A) Representative western blotting analysis of lysates derived from zebrafish embryos injected with 7 ng of control MO (Con) or those injected with increasing doses of elavl1a Mo1. Cell lysates were prepared at 24 hpf. (B) Quantification of elavl1a Mo1 knockdown efficiency based on western blotting data; results were averaged from 3 independent experiments. Error bars represent SD. *P < .05; **P < .001. (C) Semiquantitative RT-PCR demonstrates efficacy of elavl1a splicing MO (Mo2) knockdown. Amplifications were for 24 or 26 cycles. 18S RNA was measured as control. (D) Embryos that had been injected at the 1-cell stage with 4 ng of control MO are normal, whereas those injected with either Mo1 or Mo2 are defective and grossly similar at 24 hpf and 48 hpf. (E) Quantification of embryos showing characteristic developmental defects (as in panel D) caused by either of the 2 MOs. (F) Quantification of embryonic defects in embryos injected with control (Con) MO, elavl1a MO, or coinjected with elavl1a MO and murine Elavl1 mRNA. (B-F) The results are compiled from several independent experiments with n > 150.