Neuronal defects in the hindbrain ofHoxa1, Hoxb1andHoxb2mutants reflect regulatory interactions among these Hox genes

• DOI: 10.1242/dev.00802
• Publication Date: 2003-10-07T00:14:49Z
• Authors: Anthony Gavalas; Christiana Ruhrberg; Jean Livet; Christopher E. He...; Robb Krumlauf
• Keywords: Hindbrain; Ectopic expression; Rhombomere

Hox genes are instrumental in assigning segmental identity the developing hindbrain. Auto-, cross- and para-regulatory interactions help establish maintain their expression. To understand to what extent such regulatory shape neuronal patterning hindbrain, we analysed neurogenesis, differentiation motoneuron migration Hoxa1, Hoxb1 Hoxb2 mutant mice. This comparison revealed that neurogenesis of specific subpopulations r4 was impaired a similar fashion all three mutants, but with different degrees severity. In neurons derived from presumptive territory were re-specified towards an r2-like identity. Motoneurons resembled trigeminal motoneurons both patterns expression molecular markers. Both migrating resident underwent changes consistent switch r2 Abnormally initially formed ectopic nuclei subsequently cleared. Their survival could be prolonged through introduction block apoptotic pathway. The Hoxa1 phenotype is partial misspecification results activation. hypomorph phenotype, overlapping roles these facial specification. Therefore, have delineated functional requirements hindbrain follow establishment genetic hierarchy between Hoxb2.