Generation of neurons by transient expression of neural bHLH proteins in mammalian cells.
Basic helix-loop-helix (bHLH) transcription factors are known to function during mammalian neurogenesis. Here we show that transient transfection of vectors expressing neuroD2, MASH1, ngn1 or related neural bHLH proteins, with their putative dimerization partner E12, can convert mouse P19 embryonal carcinoma cells into differentiated neurons. Transfected cells express numerous neuron-specific proteins, adopt a neuronal morphology and are electrically excitable. Thus, the expression of neural bHLH proteins is sufficient to confer a neuronal fate on uncommitted mammalian cells. Neuronal differentiation of transfected cells is preceded by elevated expression of the cyclin-dependent kinase inhibitor p27(Kip1) and cell cycle withdrawal. This demonstrates that the bHLH proteins can link neuronal differentiation to withdrawal from the cell cycle, possibly by activating the expression of p27(Kip1). The ability to generate mammalian neurons by transient expression of neural bHLH proteins should create new opportunities for studying neurogenesis and devising neural repair strategies.
Farah
M H
MH
Mental Health Research Institute, Neuroscience Program, and Department of Biology, University of Michigan, Ann Arbor, MI 48104-1687, USA.
Olson
J M
JM
Sucic
H B
HB
Hume
R I
RI
Tapscott
S J
SJ
Turner
D L
DL
D000818:Animals; D001483:Base Sequence; D051792:Basic Helix-Loop-Helix Proteins; D002453:Cell Cycle; D018797:Cell Cycle Proteins; D002454:Cell Differentiation; D002460:Cell Line; D050760:Cyclin-Dependent Kinase Inhibitor p27; D018844:Cyclin-Dependent Kinases / Q000037:antagonists & inhibitors; D017931:DNA Primers / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics; D018507:Gene Expression Regulation, Developmental; D005822:Genetic Vectors; D018257:Helix-Loop-Helix Motifs / Q000235:genetics*; D051379:Mice; D008869:Microtubule-Associated Proteins / Q000235:genetics; D009419:Nerve Tissue Proteins / Q000235:genetics; D009474:Neurons / Q000166:cytology* / Q000378:metabolism*; D009479:Neuropeptides / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics*; D014162:Transfection; D025521:Tumor Suppressor Proteins
D051792:Basic Helix-Loop-Helix Proteins; D018797:Cell Cycle Proteins; D050760:Cyclin-Dependent Kinase Inhibitor p27; D018844:Cyclin-Dependent Kinases; D017931:DNA Primers; D004268:DNA-Binding Proteins; D008869:Microtubule-Associated Proteins; D009419:Nerve Tissue Proteins; D009479:Neuropeptides; D014157:Transcription Factors; D025521:Tumor Suppressor Proteins; C499317:Ascl1 protein, mouse; C493961:Cdkn1b protein, mouse; C490925:NEUROD2 protein, human; C098995:Neurod2 protein, mouse; C486336:Neurog1 protein, mouse