Identification of downstream targets of zebrafish Hoxb1a
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ABSTRACT: 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
ORGANISM(S): Danio rerio
PROVIDER: GSE5199 | GEO | 2007/01/01
SECONDARY ACCESSION(S): PRJNA96559
REPOSITORIES: GEO
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