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Na+, K+-ATPase 2 subunit gene (Atp1a2) knock-out homozygous mice (Atp1a2-/-) died immediately after birth resulting from lack of breathing. The respiratory-related neuron activity in Atp1a2-/- was investigated using a brainstem-spinal cord en bloc preparation. The respiratory motoneuron activity recorded from the fourth cervical ventral root (C4) was(More)
Phox2b protein is a specific marker for neurons in the parafacial region of the ventral medulla, which are proposed to play a role in central chemoreception and postnatal survival. Mutations of PHOX2B cause congenital central hypoventilation syndrome. However, there have been no reports concerning electrophysiological characteristics of these(More)
The members of the Six gene family were identified as homologues of Drosophila sine oculis which is essential for compound-eye formation. The Six proteins are characterized by the Six domain and the Six-type homeodomain, both of which are essential for specific DNA binding and for cooperative interactions with Eya proteins. Mammals possess six Six genes(More)
Six1 is a member of the Six family homeobox genes, which function as components of the Pax-Six-Eya-Dach gene network to control organ development. Six1 is expressed in otic vesicles, nasal epithelia, branchial arches/pouches, nephrogenic cords, somites and a limited set of ganglia. In this study, we established Six1-deficient mice and found that development(More)
The sodium pump is the enzyme responsible for the maintenance of Na+ and K+ gradients across the cell membrane. Four isoforms of the catalytic alpha subunit have been identified, but their individual roles remain essentially unknown. To investigate the necessary functions of the alpha2 subunit in vivo, we generated and analyzed mice defective in the alpha2(More)
The Six1 homeobox gene plays critical roles in vertebrate organogenesis. Mice deficient for Six1 show severe defects in organs such as skeletal muscle, kidney, thymus, sensory organs and ganglia derived from cranial placodes, and mutations in human SIX1 cause branchio-oto-renal syndrome, an autosomal dominant developmental disorder characterized by hearing(More)
All cranial sensory organs and sensory neurons of vertebrates develop from cranial placodes. In chick, amphibians and zebrafish, all placodes originate from a common precursor domain, the pre-placodal region (PPR), marked by the expression of Six1/4 and Eya1/2. However, the PPR has never been described in mammals and the mechanism involved in the formation(More)
The olfactory epithelium (OE) is derived from the olfactory placode (OP) during mouse development. At embryonic day (E) 10.0-E10.5, "early neurogenesis" occurs in the OE, which includes production of pioneer neurons that emigrate out of the OE and other early-differentiated neurons. Around E12.5, the OE becomes organized into mature pseudostratified(More)
Inner ear mechanosensory hair cells transduce sound and balance information. Auditory hair cells emerge from a Sox2-positive sensory patch in the inner ear epithelium, which is progressively restricted during development. This restriction depends on the action of signaling molecules. Fibroblast growth factor (FGF) signalling is important during sensory(More)
The Y-linked gene Sry regulates mammalian sex determination in bipotential embryonic gonads. Here, we report that the transcription factors Six1 and Six4 are required for male gonadal differentiation. Loss of Six1 and Six4 together, but neither alone, resulted in a male-to-female sex-reversal phenotype in XY mutant gonads accompanied by a failure in Sry(More)