Characterization of dendritic spines in the Drosophila central nervous system

Abstract

Dendritic spines are a characteristic feature of a number of neurons in the vertebrate nervous system and have been implicated in processes that include learning and memory. In spite of this, there has been no comprehensive analysis of the presence of spines in a classical genetic system, such as Drosophila, so far. Here, we demonstrate that a subset of processes along the dendrites of visual system interneurons in the adult fly central nervous system, called LPTCs, closely resemble vertebrate spines, based on a number of criteria. First, the morphology, size, and density of these processes are very similar to those of vertebrate spines. Second, they are enriched in actin and devoid of tubulin. Third, they are sites of synaptic connections based on confocal and electron microscopy. Importantly, they represent a preferential site of localization of an acetylcholine receptor subunit, suggesting that they are sites of excitatory synaptic input. Finally, their number is modulated by the level of the small GTPase dRac1. Our results provide a basis to dissect the genetics of dendritic spine formation and maintenance and the functional role of spines. '

Presynapses in Kenyon Cell Dendrites in the Mushroom Body Calyx of Drosophila

“…To this end, we fused the KC-specific enhancer mb247 to the gene encoding for the D␣7 acetylcholine (ACh) receptor subunit (Grauso et al, 2002;Fayyazuddin et al, 2006) (mb247::d␣7 GFP ), flanked by the gfp gene. We have already previously used D␣7 GFP to label PSDs of cholinergic synapses (Leiss et al, 2009;Raghu et al, 2009;Kremer et al, 2010). The GFP signal of mb247::d␣7 GFP was absent from the MB lobes of larvae and adults (data not shown), indicating that, as expected, ACh receptors of KCs are restricted to the calyx region.…”

“…The following fly stocks were used: c305a-GAL4 (Krashes et al, 2007), c739-GAL4 (O'Dell et al, 1995;Yang et al, 1995), gh146-GAL4 (Stocker et al, 1997), h24-GAL4 (Zars et al, 2000), ok107-GAL4 (Connolly et al, 1996), UAS-brp-RNAi (Wagh et al, 2006, recombination of B3 and C8), UAS-synapto-pHluorin (Ng et al, 2002), UAS-Da7 GFP (Leiss et al, 2009), UAS-brp-short mCherry (Schmid et al, 2008), UAS-syt GFP (Zhang et al, 2002), mb247::brp-short GFP , w,hsFlp, FRT82B,tubGAL80/ TM3,Sb;Howard Hughes Medical Institute,Stanford University, Palo Alto, CA), w Ϫ ;FRT82B (Lee and Luo, 2001). All fly strains were reared under standard laboratory conditions (Sigrist et al, 2003) at 25°C.…”

Centrosomin represses dendrite branching by orienting microtubule nucleation

“…The vertical system 1 (VS1) interneurons of the Drosophila adult visual system have a curved primary dendrite shaft from which secondary branches radiate ( Supplementary Fig. 5) 26 , and in cnn mutants the frequency of these secondary branches was increased by 51% (P < 0.0001, Fig. 2m, Supplementary Fig.…”

Long-Term Memory inDrosophilaIs Influenced by Histone Deacetylase HDAC4 Interacting with SUMO-Conjugating Enzyme Ubc9

“…Moreover, krasavietz (Dubnau et al 2003) and Ankyrin 2 (Iqbal et al 2013) are also required for memory formation. Axon and dendritic growth and branching can easily be visualized and assessed in Drosophila (Leiss et al 2009;Goossens et al 2011), which will facilitate investigation of the relationships between these genes and HDAC4.…”