Expression of the antiproliferative gene TIS21 at the onset of neurogenesis identifies single neuroepithelial cells that switch from proliferative to neuron-generating division.
At the onset of mammalian neurogenesis, neuroepithelial (NE) cells switch from proliferative to neuron-generating divisions. Understanding the molecular basis of this switch requires the ability to distinguish between these two types of division. Here we show that in the mouse ventricular zone, expression of the mRNA of the antiproliferative gene TIS21 (PC3, BTG2) (i) starts at the onset of neurogenesis, (ii) is confined to a subpopulation of NE cells that increases in correlation with the progression of neurogenesis, and (iii) is not detected in newborn neurons. Expression of the TIS21 mRNA in the NE cells occurs transiently during the cell cycle, i.e., in the G1 phase. In contrast to the TIS21 mRNA, the TIS21 protein persists through the division of NE cells and is inherited by the neurons, where it remains detectable during neuronal migration and the initial phase of differentiation. Our observations indicate that the TIS21 gene is specifically expressed in those NE cells that, at their next division, will generate postmitotic neurons, but not in proliferating NE cells. Using TIS21 as a marker, we find that the switch from proliferative to neuron-generating divisions is initiated in single NE cells rather than in synchronized neighboring cells.
Iacopetti
P
P
Department of Neurobiology, University of Heidelberg, Im Neuenheimer Feld 364, D-69120 Heidelberg, Germany.
Michelini
M
M
Stuckmann
I
I
Oback
B
B
Aaku-Saraste
E
E
Huttner
W B
WB
D000818:Animals; D000831:Animals, Newborn; D019556:COS Cells; D018797:Cell Cycle Proteins / Q000096:biosynthesis / Q000235:genetics; D002455:Cell Division; D002490:Central Nervous System / Q000166:cytology / Q000196:embryology* / Q000378:metabolism; D004847:Epithelial Cells / Q000166:cytology / Q000502:physiology; D000939:Epitopes / Q000032:analysis; D018507:Gene Expression Regulation, Developmental; D016147:Genes, Tumor Suppressor; D017874:Immediate-Early Proteins / Q000096:biosynthesis / Q000235:genetics*; D051379:Mice; D009474:Neurons / Q000166:cytology / Q000502:physiology*; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics; D011994:Recombinant Proteins / Q000096:biosynthesis; D014158:Transcription, Genetic; D014162:Transfection; D025521:Tumor Suppressor Proteins
C489435:Btg2 protein, mouse; D018797:Cell Cycle Proteins; D000939:Epitopes; D017874:Immediate-Early Proteins; D012333:RNA, Messenger; D011994:Recombinant Proteins; D025521:Tumor Suppressor Proteins