Hoxa1 and Hoxb1 synergize in patterning the hindbrain, cranial nerves and second pharyngeal arch

• DOI: 10.1242/dev.125.6.1123
• Publication Date: 2021-04-23T19:45:11Z
• Authors: Anthony Gavalas; Michèle Studer; Andrew Lumsden; Filippo M. Rijli; Robb Krumlauf; Pierre Chambon
• Keywords: Rhombomere; Hindbrain

The analysis of Hoxa1 and Hoxb1 null mutants suggested that these genes are involved in distinct aspects hindbrain segmentation specification. Here we investigate the possible functional synergy two genes. generation Hoxa1(3'RARE)/Hoxb1(3'RARE) compound resulted mild facial motor nerve defects reminiscent those present mutants. Strong genetic interactions between were uncovered by introducing Hoxb1(3'RARE) mutations into background. Hoxa1(null)/Hoxb1(3'RARE) Hoxa1(null)/Hoxb1(null )double homozygous embryos showed additional patterning r4-r6 region but maintained a molecularly r4-like territory. Neurofilament staining retrograde labelling neurons indicated synergise VIIth through XIth cranial nerves. second arch expression neural crest cell markers was abolished or dramatically reduced, suggesting defect this population. Strikingly, double mutant involuted 10.5 dpc loss all arch-derived elements complete disruption external middle ear development. Additional defects, most notably lack tympanic ring, found first elements, take place during Taken together, our results unveil an extensive not anticipated from phenotypes simple