title: A combinatorial regulatory signature controls terminal differentiation of the dopaminergic nervous system in C. elegans.
abstract: Terminal differentiation programs in the nervous system are encoded by cis-regulatory elements that control the expression of terminal features of individual neuron types. We decoded the regulatory information that controls the expression of five enzymes and transporters that define the terminal identity of all eight dopaminergic neurons in the nervous system of the Caenorhabditis elegans hermaphrodite. We show that the tightly coordinated, robust expression of these dopaminergic enzymes and transporters ("dopamine pathway") is ensured through a combinatorial cis-regulatory signature that is shared by all dopamine pathway genes. This signature is composed of an Ets domain-binding site, recognized by the previously described AST-1 Ets domain factor, and two distinct types of homeodomain-binding sites that act in a partially redundant manner. Through genetic screens, we identified the sole C. elegans Distalless/Dlx ortholog, ceh-43, as a factor that acts through one of the homeodomain sites to control both induction and maintenance of terminal dopaminergic fate. The second type of homeodomain site is a Pbx-type site, which is recognized in a partially redundant and neuron subtype-specific manner by two Pbx factors, ceh-20 and ceh-40, revealing novel roles of Pbx factors in the context of terminal neuron differentiation. Taken together, we revealed a specific regulatory signature and cognate, terminal selector-type transcription factors that define the entire dopaminergic nervous system of an animal. Dopaminergic neurons in the mouse olfactory bulb express a similar combinatorial transcription factor collective of Ets/Dlx/Pbx factors, suggesting deep phylogenetic conservation of dopaminergic regulatory programs.
authors.affiliation: Department of Biochemistry and Molecular Biophysics, Columbia University Medical Center, New York, NY 10032, USA. maria.doitsidou@uis.no
authors.forename: Maria
authors.initials: M
authors.lastname: Doitsidou
authors.forename: Nuria
authors.initials: N
authors.lastname: Flames
authors.forename: Irini
authors.initials: I
authors.lastname: Topalidou
authors.forename: Namiko
authors.initials: N
authors.lastname: Abe
authors.forename: Terry
authors.initials: T
authors.lastname: Felton
authors.forename: Laura
authors.initials: L
authors.lastname: Remesal
authors.forename: Tatiana
authors.initials: T
authors.lastname: Popovitchenko
authors.forename: Richard
authors.initials: R
authors.lastname: Mann
authors.forename: Martin
authors.initials: M
authors.lastname: Chalfie
authors.forename: Oliver
authors.initials: O
authors.lastname: Hobert
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017173:Caenorhabditis elegans / Q000166:cytology / Q000196:embryology* / Q000235:genetics* / Q000378:metabolism; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism; D002454:Cell Differentiation / Q000235:genetics; D004252:DNA Mutational Analysis; D059290:Dopaminergic Neurons / Q000166:cytology* / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D008969:Molecular Sequence Data; D009420:Nervous System / Q000166:cytology / Q000196:embryology*; D050436:Regulatory Elements, Transcriptional / Q000235:genetics; D016415:Sequence Alignment
chemical_list: D029742:Caenorhabditis elegans Proteins
keywords: cis-regulatory motif; differentiation; dopamine; elegans; homeodomain; neuron