High impact information on Hmx2

• Hmx2, a member of the Hmx homeobox gene family, is coexpressed with Hmx3 in the dorsolateral otic epithelium [1].
• In Hmx2 null embryos, a perturbation in cell fate determination in the lateral aspect of the otic epithelium results in reduced cell proliferation in epithelial cells, which includes the vestibular sensory patches and semicircular duct fusion plates, as well as in the adjacent mesenchyme [1].
• Both Hmx2 and Hmx3 transcripts are coexpressed in the developing central nervous system including the neural tube and hypothalamus [1].
• Hmx2 homeobox gene control of murine vestibular morphogenesis [1].
• The mouse Nkx-5.1 and Nkx-5.2 genes have been identified by sequence homology to Drosophila NK genes within the homeobox domain [2].

Biological context of Hmx2

• During evolution, mouse Hmx2 and Hmx3 may have retained a primary function in central nervous system development as suggested by their expression in the postmitotic cells of the neural tube, as well as in the hypothalamus, the mesencephalon, metencephalon and discrete regions in the myelencephalon during embryogenesis [3].
• Assignment of the murine Hmx2 and Hmx3 homeobox genes to the distal region of mouse chromosome 7 [4].

Anatomical context of Hmx2

• Compound Hmx2 and Hmx3 double mutant mice showed more severe defects in the inner ear than those displayed by either single knockout [5].
• Nkx5-1 and Nkx5-2 are also expressed in the cochlea, where the expression is restricted to the stria vascularis [6].

Co-localisations of Hmx2

• Nkx-5.2 transcripts are first detected in E13.5 embryos where they colocalize with Nkx-5.1 mRNA in the developing central nervous system and the inner ear [2].

Other interactions of Hmx2

• Transgenic mouse lines were generated to examine the DNA regulatory elements controlling Hmx2 and Hmx3 [3].
• Regionalized expression of Nkx5-1, Nkx5-2, Pax2 and sek genes during mouse inner ear development [6].
• However, more typically there is redundancy of gene action during inner ear development as exemplified by the overlapping pattern of expression of two closely related homeobox-containing genes (i.e. Hmx2 and Hmx3) in the pars superior of the otocyst [7].

References