Project description:This study analyzed mRNA profiles in rhombomere 4 of E10.5 mouse knock-in embryos expressing either normal endogenous Hox-B1 protein or the paralogous Hox-A1 protein from the Hoxb1 locus. The Hox-A1 protein was found to be detectably less efficacious than Hox-B1 in promoting neurogenesis in the basal plate of rhombomere 4 and its transcriptional profile shared several similarities with the Hoxb1 mutant. Keywords: gene swap, knock-in, hindbrain development, rhombomere 4
Project description:This study analyzed mRNA profiles in rhombomere 4 of E10.5 mouse knock-in embryos expressing either normal endogenous Hox-B1 protein or the paralogous Hox-A1 protein from the Hoxb1 locus. The Hox-A1 protein was found to be detectably less efficacious than Hox-B1 in promoting neurogenesis in the basal plate of rhombomere 4 and its transcriptional profile shared several similarities with the Hoxb1 mutant. Experiment Overall Design: GFP-positive cells were FACS-sorted from dissected hindbrains of entire litters of E10.5 mouse embryos expressing either normal endogenous Hox-B1 protein or the paralogous Hox-A1 protein from the Hoxb1 locus, either one tagged with IRES-tauGFP. Three independent biological replicates of each genotype were analyzed. Total RNA was isolated, amplified and hybridized to Affymetrix Mouse Genome 430 2.0 Arrays.
Project description:Hoxb1 is required for proper specification of rhombomere 4 and the facial motor neurons. This study analyzed gene expression in the corresponding hindbrain segment of E10.5 mutant embryos. Several genetic pathways were found altered, including transcription factors such as Phox2b, Gata3, Nkx2-2 and Nkx6-1. Keywords: hindbrain development, rhombomere 4, Hoxb1
Project description:Hoxb1 is required for proper specification of rhombomere 4 and the facial motor neurons. This study analyzed gene expression in the corresponding hindbrain segment of E10.5 mutant embryos. Several genetic pathways were found altered, including transcription factors such as Phox2b, Gata3, Nkx2-2 and Nkx6-1. Experiment Overall Design: Each of the three mutant and control samples was an independent biological replicate. Pools of r4 segments from multiple embryos were snap frozen on dry ice and stored at -80ºC. Total RNA was isolated, processed with standard Affymetrix protocols and hybridized to GeneChip Mouse Expression Sets 430A.
Project description:Despite 30 years of Hox gene study we have a remarkably limited knowledge of the downstream target genes that Hox transcription factors regulate to confer regional identity. Here, we have used a microarray approach to identify genes that function downstream of a single vertebrate Hox gene, zebrafish hoxb1a. This gene plays a critical and conserved role in vertebrate hindbrain development, conferring identity to hindbrain rhombomere 4. For example, zebrafish Hoxb1a, similar to mouse Hoxb1, is required for the migration of r4-derived facial branchiomotor neurons into the posterior hindbrain. We have screened microarrays carrying more than 16,000 expressed sequence tags (ESTs) for genes that are differentially regulated in normal versus Hoxb1a-deficient rhombomere 4 tissue. Using this approach, we have identified both positively and negatively regulated candidate Hoxb1a target genes. We have used in situ hybridization to validate twelve positively regulated Hoxb1a targets. These downstream targets are expressed in a variety of subdomains within r4, with one gene, a novel prickle homolog (pk1b), expressed specifically within the facial branchiomotor neurons. Using morpholino knock-down we show that the Hoxb1a target Pk1b is required for facial neuron migration, a single aspect of rhombomere 4 identity. Keywords: Comparison of normal and Hox-deficient tissue
Project description:Following neural tube closure at around E9.5, the rhombic lip within the rhombomere 1/isthmus region ("upper rhombic lip") produces a sequence of neuronal lineages that populate the brainstem and cerebellum. The transcription factor Atoh1 (Math1) is required for this specialized neurogenesis, although the genetic programs that delineate the temporal cell fate changes downstream of Atoh1 are not well characterized. We examined the gene expresion changes that take place within Atoh1 lineages We purified early (E10.5) and late (E13.5) born Atoh1 expressing cells from E14.5 embryos using a transgenic labeling strategy, and analyzed differences in gene expression across the two populations using the microarray data shown below.