LEF/TCF family transcription factors are important in the upregulation and restricted expression of zic genes in the dorsal neural tube
A central question in biology is how different cell-types arise from an initially one-celled embryo to form an organism. Many cellular differences arise through differential gene expression in space and time via the action of transcription factors (TFs). Zic genes are TFs that contribute to the patterning of the developing vertebrate nervous system, but little is known about how their transcription is regulated. Consensus scoring across several vertebrate species identified possible loci for TF binding sites within a previously identified stretch of zic regulatory DNA, cis-regulatory module D5. The three most promising sites were mutated and injected in constructs upstream of eGFP reporters into zebrafish embryos at the one cell stage. Expression was observed in F1 transgenics by in vivo fluorescence at approximately 24 hrs. The mutation of the LEF TF binding site suggests that Zic expression is upregulated and restricted to the dorsal neural tube by action of LEF TFs.