Mammalian BarH1 confers commissural neuron identity on dorsal cells in the spinal cord.
Commissural neurons in the spinal cord project their axons through the floor plate using a number of molecular interactions, such as netrins and their receptor DCC (deleted in colorectal cancer). However, the molecular cascades that control differentiation of commissural neurons are less characterized. A homeobox gene, MBH1 (mammalian BarH1) was expressed specifically in a subset of dorsal cells in the developing spinal cord. Transgenic mice that carried lacZ and MBH1-flanking genome sequences demonstrated that MBH1 was expressed by commissural neurons. To analyze the function of MBH1, we established an in vivo electroporation method for the transfer of DNA into the mouse spinal cord. Ectopic expression of MBH1 drove dorsal cells into the fate of commissural neurons with concomitant expression of TAG-1 (transiently expressed axonal surface glycoprotein 1) and DCC. Cells ectopically expressing MBH1 migrated to the deep dorsal horn, in which endogenous MBH1-positive cells accumulated. These results suggest that MBH1 functions upstream of TAG-1 and DCC and is involved in the fate determination of commissural neurons in the spinal cord.
Saba
Rie
R
Department of Genetics, The Graduate University for Advanced Studies, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan.
Nakatsuji
Norio
N
Saito
Tetsuichiro
T
D024509:3' Flanking Region; D024506:5' Flanking Region; D000818:Animals; D000943:Antigens, Differentiation / Q000235:genetics / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology; D002465:Cell Movement / Q000187:drug effects / Q000502:physiology; D029721:Drosophila Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000494:pharmacology; D018274:Electroporation / Q000379:methods; D005136:Eye Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000494:pharmacology; D018014:Gene Transfer Techniques; D017930:Genes, Reporter; D018398:Homeodomain Proteins; D007278:Injections, Spinal; D008164:Luminescent Proteins / Q000235:genetics; D051379:Mice; D008822:Mice, Transgenic; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D020671:Posterior Horn Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000235:genetics; D013116:Spinal Cord / Q000166:cytology / Q000196:embryology / Q000378:metabolism*; D014157:Transcription Factors; D019076:Transgenes / Q000502:physiology; D001616:beta-Galactosidase / Q000096:biosynthesis / Q000235:genetics
D000943:Antigens, Differentiation; C072318:B-H1 protein, Drosophila; D029721:Drosophila Proteins; D005136:Eye Proteins; D018398:Homeodomain Proteins; D008164:Luminescent Proteins; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; D001616:beta-Galactosidase