Identification of Phox2b-regulated genes by expression profiling of cranial motoneuron precursors on NIA 15k microarray

Branchiomotor neurons are an important class of cranial motor neurons that innervate the branchial-arch-derived muscles of the face, jaw and neck. They arise in the ventralmost progenitor domain of the rhombencephalon characterized by expression of the homeodomain transcription factors Nkx2.2 and Phox2b. Phox2b in particular plays a key role in the specification of branchiomotor neurons. In its absence, generic neuronal differentiation is defective in the progenitor domain, and no branchiomotor neurons are produced. Conversely, ectopic expression of Phox2b in spinal regions of the neural tube promotes cell cycle exit and neuronal differentiation and at the same time induces genes and an axonal phenotype characteristic for branchiomotor neurons. How Phox2b exerts its pleiotropic functions, both as a proneural gene and a neuronal subtype determinant, has remained unknown. To gain further insight into the genetic programme downstream of Phox2b we searched for novel Phox2b-regulated genes by cDNA microarray (here NIA 15k slides) analysis of facial branchiomotor neuron precursors from heterozygous and homozygous Phox2b mutant embryos. Keywords: Phox2b-regulated genes identification Four biological replicates each in dye swap