Linking asymmetric cell division to the terminal differentiation program of postmitotic neurons in C. elegans.
How asymmetric divisions are connected to the terminal differentiation program of neuronal subtypes is poorly understood. In C. elegans, two homeodomain transcription factors, TTX-3 (a LHX2/9 ortholog) and CEH-10 (a CHX10 ortholog), directly activate a large battery of terminal differentiation genes in the cholinergic interneuron AIY. We establish here a transcriptional cascade linking asymmetric division to this differentiation program. A transient lineage-specific input formed by the Zic factor REF-2 and the bHLH factor HLH-2 directly activates ttx-3 expression in the AIY mother. During the terminal division of the AIY mother, an asymmetric Wnt/beta-catenin pathway cooperates with TTX-3 to directly restrict ceh-10 expression to only one of the two daughter cells. TTX-3 and CEH-10 automaintain their expression, thereby locking in the differentiation state. Our study establishes how transient lineage and asymmetric division inputs are integrated and suggests that the Wnt/beta-catenin pathway is widely used to control the identity of neuronal lineages.
Bertrand
Vincent
V
Department of Biochemistry and Molecular Biophysics, Howard Hughes Medical Institute, Columbia University Medical Center, New York, NY 10032, USA. vb2157@columbia.edu
Hobert
Oliver
O
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D017173:Caenorhabditis elegans / Q000166:cytology* / Q000196:embryology; D029742:Caenorhabditis elegans Proteins / Q000378:metabolism; D002454:Cell Differentiation; D004625:Embryo, Nonmammalian / Q000166:cytology / Q000378:metabolism; D005260:Female; D007395:Interneurons / Q000166:cytology / Q000378:metabolism; D008938:Mitosis; D008954:Models, Biological; D008969:Molecular Sequence Data; D009474:Neurons / Q000166:cytology* / Q000378:metabolism; D051153:Wnt Proteins / Q000378:metabolism; D051176:beta Catenin / Q000378:metabolism
D029742:Caenorhabditis elegans Proteins; D051153:Wnt Proteins; D051176:beta Catenin