Molecules and mechanisms of dendrite development inDrosophila

Abstract

Neurons are one of the most morphologically diverse cell types, in large part owing to their intricate dendrite branching patterns. Dendrites are structures that are specialized to receive and process inputs in neurons, thus their specific morphologies reflect neural connectivity and influence information flow through circuits. Recent studies in Drosophila on the molecular basis of dendrite diversity, dendritic guidance, the cell biology of dendritic branch patterning and territory formation have identified numerous intrinsic and extrinsic cues that shape diverse features of dendrites. As we discuss in this review, many of the mechanisms that are being elucidated show conservation in diverse systems. IntroductionDendrites -processes of neurons that are primarily specialized for information input -are one of nature's remarkable architectural feats, and the diverse growth patterns shown by dendritic arbors raise important developmental questions. The particular shapes of dendrites are important in neuronal function and circuit assembly. Their targets and complexity influence the range of inputs that a neuron receives. In addition, the morphology of a dendritic arbor can impact the processing and integration of electrical signals (London and Häusser, 2005). Studies of dendrite morphogenesis therefore seek to understand the developmental origin of arbor shape and to shed light on the significance of particular morphologies for nervous system connectivity and function.Dendrite morphogenesis consists of a series of interrelated steps, which include outgrowth and branching, guidance and targeting, cessation of growth and, in some cases, arbor remodeling (see Box 1). Each process is under extensive genetic regulation and has been the subject of intensive study in recent years. In this review, we highlight recent advances in understanding the molecules and mechanisms that function during these key stages of dendrite morphogenesis. We focus primarily on studies carried out in Drosophila (Fig. 1) and refer to known or emerging areas of conservation in vertebrate systems where appropriate. We focus on several key questions, including: what are the cell biological mechanisms that specify the distribution of dendritic branches along an arbor? How do dendrites achieve typespecific branching patterns? How is specific dendritic targeting controlled in different neurons? How are dendrites instructed when to stop branching and growing? How does activity impact dendrite development in Drosophila? We refer readers to other reviews that cover topics that have thus far been studied primarily in vertebrate systems, including dendritic spine morphogenesis and activitydependent dendrite growth (Alvarez and Sabatini, 2007;Chen and Ghosh, 2005;Flavell and Greenberg, 2008;Lippman and Dunaevsky, 2005;Redmond, 2008). Genetic insights into the cell biology of dendrite growth and branchingThe growth and specialized functions of dendritic arbors can require large investments of dendritic plasma membrane and proteins during development, and, inde...

Temporal coherency between receptor expression, neural activity and AP-1-dependent transcription regulatesDrosophilamotoneuron dendrite development

“…The development of dendritic structure is influenced by multiple intrinsic and external factors, including neural activity (Cline, 2001;West et al, 2002;Chen and Ghosh, 2005;Sanyal and Ramaswami, 2006). The Drosophila genetic model has yielded useful insights into the molecular basis underlying neuron type-specific dendritic morphology (Moore et al, 2002;Jefferis et al, 2001;, dendritic spacing (Zhu and Luo, 2004;Grueber et al, 2002;Grueber et al, 2003;Corty et al, 2009) and dendritic guidance (Komiyama et al, 2002;Sweeney et al, 2002;Furrer et al, 2003;Mauss et al, 2009;Brierley et al, 2009). By contrast, few studies have addressed the role of neuronal activity during dendritic development in the Drosophila CNS (Tripodi et al, 2008;Hartwig et al, 2008;Duch et al, 2008).…”

C. elegans bicd-1, homolog of theDrosophiladynein accessory factorBicaudal D, regulates the branching of PVD sensory neuron dendrites

“…Dendritic branching represents a key step(s) in the formation of dendritic arbors. Whereas studies in Drosophila and vertebrate systems have identified a variety of molecules that regulate dendrite branching (Corty et al, 2009;Jan and Jan, 2010;Urbanska et al, 2008), the full repertoire of molecules controlling this crucial stage of dendrite development remains obscure.…”

Transcription factors and effectors that regulate neuronal morphology

“…The dendritic arborization (da) sensory neurons of Drosophila larvae provide a powerful model for understanding the acquisition of dendritic morphology (Corty et al, 2009;Jan and Jan, 2010). These dendrites form a largely two-dimensional array between the body wall muscles and the epidermis.…”