TY - JOUR
T1 - Expression of major guidance receptors is differentially regulated in spinal commissural neurons transfated by mammalian Barh genes
AU - Kawauchi, Daisuke
AU - Muroyama, Yuko
AU - Sato, Tatsuya
AU - Saito, Tetsuichiro
N1 - Funding Information:
We are grateful to Drs. S. Miyagi and T. Chiba for advice on quantitative PCR. We also acknowledge the Developmental Studies Hybridoma Bank maintained by the University of Iowa for supply of an antibody. This work was supported by JSPS KAKENHI 20240029 and the Mitsubishi Foundation. (to T. S.).
PY - 2010/8
Y1 - 2010/8
N2 - During development, commissural neurons in the spinal cord project their axons across the ventral midline, floor plate, via multiple interactions among temporally controlled molecular guidance cues and receptors. The transcriptional regulation of commissural axon-associated receptors, however, is not well characterized. Spinal dorsal cells are transfated into commissural neurons by misexpression of Mbh1, a Bar-class homeobox gene. We examined the function of another Bar-class homeobox gene, Mbh2, and how Mbh1 and Mbh2 modulate expression of the receptors, leading to midline crossing of axons. Misexpression of Mbh1 and Mbh2 showed the same effects in the spinal cord. The competence of spinal dorsal cells to become commissural neurons was dependent on the embryonic stage, during which misexpression of the Mbh genes was able to activate guidance receptor genes such as Rig1 and Nrp2. Misexpression of Lhx2, which has been recently shown to be involved in Rig1 expression, activated Rig1 but not Nrp2, and was less effective in generating commissural neurons. Moreover, expression of Lhx2 was activated by and required the Mbh genes. These findings have revealed a transcriptional cascade, in which Lhx2-dependent and -independent pathways leading to expression of guidance receptors branch downstream of the Mbh genes.
AB - During development, commissural neurons in the spinal cord project their axons across the ventral midline, floor plate, via multiple interactions among temporally controlled molecular guidance cues and receptors. The transcriptional regulation of commissural axon-associated receptors, however, is not well characterized. Spinal dorsal cells are transfated into commissural neurons by misexpression of Mbh1, a Bar-class homeobox gene. We examined the function of another Bar-class homeobox gene, Mbh2, and how Mbh1 and Mbh2 modulate expression of the receptors, leading to midline crossing of axons. Misexpression of Mbh1 and Mbh2 showed the same effects in the spinal cord. The competence of spinal dorsal cells to become commissural neurons was dependent on the embryonic stage, during which misexpression of the Mbh genes was able to activate guidance receptor genes such as Rig1 and Nrp2. Misexpression of Lhx2, which has been recently shown to be involved in Rig1 expression, activated Rig1 but not Nrp2, and was less effective in generating commissural neurons. Moreover, expression of Lhx2 was activated by and required the Mbh genes. These findings have revealed a transcriptional cascade, in which Lhx2-dependent and -independent pathways leading to expression of guidance receptors branch downstream of the Mbh genes.
KW - Bar-class homeobox
KW - Commissural neuron
KW - Guidance receptor
KW - In vivo electroporation
KW - LIM homeobox
KW - Spinal cord
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U2 - 10.1016/j.ydbio.2010.06.025
DO - 10.1016/j.ydbio.2010.06.025
M3 - Article
C2 - 20599893
AN - SCOPUS:77955274246
VL - 344
SP - 1026
EP - 1034
JO - Developmental Biology
JF - Developmental Biology
SN - 0012-1606
IS - 2
ER -