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: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:We found that, whereas Hoxb1 does not affect NMP specification per se, it promotes NMP survival through the upregulation of Fgf8 and other components of Fgf signaling as well as the repression of components of the apoptotic pathway. Additionally, it upregulates the expression of some, primarily anterior, Hox genes suggesting that it plays an active role in the early steps of AP specification. In hindbrain neural progenitors Hoxb1 synergizes with shh to repress the expression of dorsal markers, regulate the expression of ventral markers and direct the specification of facial branchiomotorneuron (FBM) - like progenitors. Additionally, Hoxb1 and shh synergize in regulating the expression of diverse signals and signaling molecules in neural progenitors, including the Ret tyrosine kinase receptor. Hoxb1 synergizes with GDNF to strengthen Ret expression and further promote the generation of facial branchiomotorneuron (FBM) – like progenitors
Project description:Heart formation requires input from two populations of progenitor cells - the first and second heart fields - that differentiate at distinct times and create different cardiac components. The cardiac outflow tract (OFT) is built through recruitment of late-differentiating, second heart field (SHF) -derived cardiomyocytes to the arterial pole of the heart. Mechanisms responsible for selection of an appropriate number of OFT cells from the SHF remain unclear, although several lines of evidence emphasize the importance of FGF signaling in promoting this process. Here, we examine the impact of inhibition of FGF signaling on cardiac transcription profiles in an effort to identify genes operating downstream of FGF during OFT development. We compared hearts from embryos treated with the FGFR inhibitor SU5402 to the hearts from sibling embryos treated with DMSO. Two replicates were performed.
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.
