High impact information on Hmx

• The Hmx homeobox gene family is of ancient origin, being present in species as diverse as Drosophila, sea urchin and mammals [1].
• During vertebrate evolution, the Hmx genes appear to have been recruited into additional roles in inner ear morphogenesis and specification of vestibular inner ear sensory and supporting cell types [2].
• Expression domains of Hmx genes in distantly related species such as Drosophila and mouse suggest an ancestral function in rostral central nervous system development [2].
• Hmx1 has diverged from other Hmx members by its expression in the dorsal root, sympathetic and vagal nerve (X) ganglia [3].
• Drosophila Hmx was mapped to the 90B5 region of Chromosome 3 and at early embryonic stages is primarily expressed in distinct areas of the neuroectoderm and subsets of neuroblasts in the developing fly brain [3].

Biological context of Hmx

• Our work suggests that the evolution of the vertebrate inner ear may have involved (1) the redeployment of ancient Hmx activities to regulate the cell proliferation of structural components and (2) the acquisition of additional, vertebrate-specific Hmx activities to regulate the sensory epithelia [4].

Anatomical context of Hmx

• Aside from their expression in the developing nervous system, all three Hmx genes display expression in sensory organ development, and in the adult uterus [3].
• Hmx homeobox gene function in inner ear and nervous system cell-type specification and development [2].

References