The gene for the helix-loop-helix protein, Id, is specifically expressed in neural precursors.
While mammalian neurogenesis has been characterized extensively, the molecules involved in regulating neural cell determination and differentiation remain ill-defined. There is accruing evidence that various members of the basic helix-loop-helix (bHLH) protein family critically regulate these biological processes in a number of tissues. Id, a negative regulator of bHLH proteins, was found to exhibit peak gene expression during mouse embryogenesis with a striking pattern in the central nervous system. Id transcripts were specifically localized to undifferentiated neural precursors of the ventricular zone and were not present in their differentiated derivatives. In addition, in the peripheral nervous system, dorsal root ganglia sensory precursors, known to be undifferentiated while dividing, also expressed Id mRNA. However, in the sympathetic nervous system and adrenal medulla, where differentiation and division occur simultaneously in precursors, Id was not expressed. Since Id transcript abundance inversely correlated with differentiation, this protein, similar to its Drosophila homolog, extramacrochaetae, may play a negative regulatory role in neural differentiation.
Duncan
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M
Department of Biochemistry, University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, Piscataway 08854.
DiCicco-Bloom
E M
EM
Xiang
X
X
Benezra
R
R
Chada
K
K
D000818:Animals; D002454:Cell Differentiation / Q000235:genetics; D002490:Central Nervous System / Q000196:embryology*; D004268:DNA-Binding Proteins / Q000032:analysis / Q000235:genetics* / Q000378:metabolism; D005786:Gene Expression Regulation; D051798:Inhibitor of Differentiation Protein 1; D051379:Mice; D012333:RNA, Messenger / Q000032:analysis; D012097:Repressor Proteins; D013564:Sympathetic Nervous System / Q000196:embryology; D014157:Transcription Factors
D004268:DNA-Binding Proteins; C497455:Idb1 protein, mouse; D051798:Inhibitor of Differentiation Protein 1; D012333:RNA, Messenger; D012097:Repressor Proteins; D014157:Transcription Factors