Abstract
The genomic program for development operates mainly by the regulated expression of genes encoding transcription factors and the signaling pathways. Complex genetic regulatory networks control developmental fate. In this study we built the mesendoderm GRNs in zebrafish by integration of the spatial and temporal expression pattern with the interaction relationship from literatures searching and perturbation analysis. We established the subcircuits between specific transcription factors using morpholinos against them, and measured certain gene expression profiles by real time quantitative RT-PCR (Q-PCR) and validation by in situ hybridization. From our experiments, we confirmed some interactions identified from literature, and we also identified new target genes downstream of those candidates, which were not found in the literatures search. Some of the interaction nodes were identified through computational searching of the conserved non-coding region, and validated by functional analysis. This is the systematic approach towards transcriptional regulation in zebrafish development and it gives new insight to evolution of deuterostome.