Microarray analysis of Med23 mutation in E9.5 mouse embryos relative to control littermates

Development of the vertebrate head is a complex and dynamic process, which requires integration of all three germ layers and their derivatives. Of special importance are ectoderm-derived cells that form the cranial placodes, which then differentiate into the cranial ganglia and sensory organs. Critical to a fully functioning head, defects in cranial placode and sensory organ development can result in congenital craniofacial anomalies. In a forward genetic screen aimed at identifying novel regulators of craniofacial development, we discovered an embryonically lethal mouse mutant, snouty, which exhibits malformation of the facial prominences, cranial nerves and vasculature. The snouty mutation was mapped to a single nucleotide change in a ubiquitously expressed gene, Med23, which encodes a subunit of the global transcription co-factor complex, Mediator. This experiment examines transcriptional differences between Med23 mutant mice and their wt littermates at embryonic day 9.5. Two wt and three Med23 mutant embryos are compared across 6 microarrays using a dye swap strategy. The third mutant is compared to a mixture of the 1st and 2nd wt replicates.