Fig. 1

Developmental expression of zebrafish klf8, and abnormal morphology in klf8 knockdown embryos. (A–E) Spatiotemporal expression profile of klf8 in wild type (WT) embryos (lateral view). (A) At the 10 somite stage (10 ss), klf8 is expressed in the brain, optic vesicle, and somite. (B, C) klf8 is detected in the retinae, forebrain, midbrain, and hindbrain from 24 to 32 hpf. (D) At 48 hpf, klf8 is also expressed in the intestine. (E) At 72 hpf, klf8 is also expressed in the liver and intestine. (F–J) At 24 hpf, klf8 knockdown embryos exhibited abnormal cerebellar primordium morphology (arrow heads) and smaller eyes (arrows). Lateral views of un-injected WT embryos (F), and embryos injected with klf8-4mmMO1 (G), klf8-MO1^atg (H), klf8-MO2^atg (I), or co-injected with klf8-MO^AC and klf8-MO^DO (J). (K–N) Analysis of the specificity of klf8-MO1^atg and klf8-MO2^atg. EGFP is expressed in embryos injected with CMV-klf8-mo-GFP expression plasmid alone (K) or co-injected with klf8-4mmMO1 and CMV-klf8-mo-GFP plasmid (L). Green fluorescence is not observed in embryos co-injected with CMV-klf8-mo-GFP and klf8-MO1^atg (M) or klf8-MO2^atg (N). (O) Evaluation of the efficiency of klf8-MO^AC and klf8-MO^DO by RT-PCR; three aberrant transcripts (arrows) were detected in embryos co-injected with klf8-MO^AC and klf8-MO^DO. Sequencing revealed that the large (yellow arrow) and small (red arrow) transcripts contain premature stop codons, while the medium (green arrow) transcripts are comprised of wild type klf8 mRNA and a transcript with a premature stop codon. The percentage of embryos showing the indicated morphology or pattern of expression is shown in the respective panels (F–N). B, brain; h, hindbrain; i, intestine; l, liver; mhb, midbrain/hindbrain boundary; ov, optic vesicle; r, retina; s, somite.