Identification of Hoxa1 downstream targets

To better understand the role of Hoxa1 during embryogenesis and gain insight to the transcriptional network controlled by this gene, we carried out a large-scale screening for Hoxa1 downstream targets by performing microarray analysis. Tissue from the rhombomere 3-5 region of wildtype and Hoxa1 null embryos, including neuroectoderm, mesoderm and otic ectoderm was microdissected at the peak of Hoxa1 expression. RNA from wildtype and Hoxa1Δ/Δ samples was hybridized to the Agilent mouse whole genome array. Tissue from the rhombomere 3-5 region of wildtype and Hoxa1 null embryos, including neuroectoderm, mesoderm and otic ectoderm was microdissected at the peak of Hoxa1 expression (1-6 somite stage).