The selector gene cut represses a neural cell fate that is specified independently of the Achaete-Scute-Complex and atonal

Abstract

The peripheral nervous system (PNS) of Drosophila offers a powerful system to precisely identify individual cells and dissect their genetic pathways of development. The mode of specification of a subset of larval PNS cells, the multiple dendritic (md) neurons (or type II neurons), is complex and still poorly understood. Within the dorsal thoracic and abdominal segments, two md neurons, dbd and dda1, apparently require the proneural gene amos but not atonal (ato) or Achaete-Scute-Complex (ASC) genes. ASC normally acts via the neural selector gene cut to specify appropriate sensory organ identities. Here, we show that dbd- and dda1-type differentiation is suppressed by cut in dorsal ASC-dependent md neurons. Thus, cut is not only required to promote an ASC-dependent mode of differentiation, but also represses an ASC- and ato-independent fate that leads to dbd and dda1 differentiation.

Distinct Developmental Modes and Lesion-Induced Reactions of Dendrites of Two Classes ofDrosophilaSensory Neurons

“…Thus, studies on genetic programming of dendritic pattern formation would be facilitated by identifying class selector genes and searching for their downstream targets. A search for molecules that are expressed in either one of the classes may isolate regulators that switch between class-specific features; such candidates may include pdm1 and cut (Brewster et al, 2001;Grueber et al, 2002).…”

Notch-dependent downregulation of the homeodomain gene cut is required for the mitotic cycle/endocycle switch and cell differentiation inDrosophilafollicle cells

“…In wing imaginal discs, it is induced by Notch signaling at the dorsal-ventral (DV) border to maintain the DV boundary (de Celis and Bray, 1997;de Celis et al, 1996). During neurogenesis, Cut is involved in sensory organ differentiation, a process for which Notch function is also required (Blochlinger et al, 1991;Brewster et al, 2001). In addition, Cut expression has been found in follicle cells.…”

Dendritic diversification through transcription factor-mediated suppression of alternative morphologies

“…For this cell, the dendritic transformation phenotype was observed in only a subset of MARCM clones (transformation n=12/15), and ectopic expression of Pdm1/2 was observed only in transformed clones . Ectopic expression of Cut was sufficient to suppress Pdm1/2 expression (Brewster et al, 2001) and promote ectopic dendritic branching in dmd1 and dbd neurons ( Fig. 2M-P).…”

“…Cut has been shown to repress Pdm1 [Nubbin (Nub) -FlyBase] in embryonic sensory neurons (Brewster et al, 2001), prompting us to study this factor and the closely related transcription factor Pdm2 (collectively Pdm1/2) in more detail. Pdm1/2 are normally co-expressed in dbd and dmd1 sensory neurons, both of which are Cut − and predicted to function as proprioceptors (Billin et al, 1991;Dick et al, 1991;Brewster et al, 2001;Hughes and Thomas, 2007).…”

“…Pdm1/2 are normally co-expressed in dbd and dmd1 sensory neurons, both of which are Cut − and predicted to function as proprioceptors (Billin et al, 1991;Dick et al, 1991;Brewster et al, 2001;Hughes and Thomas, 2007). dbd resides along a connective tissue strand and extends dendrites in a simple bipolar fashion to span each segment (Schrader and Merritt, 2007).…”