Elsevier

Gene Expression Patterns

Volume 10, Issues 7–8, October–December 2010, Pages 328-337
Gene Expression Patterns

Targeting expression to projection neurons that innervate specific mushroom body calyx and antennal lobe glomeruli in larval Drosophila

https://doi.org/10.1016/j.gep.2010.07.004Get rights and content

Abstract

The first and secondary olfactory centers in the olfactory pathway in Drosophila are organized into neuropil structures called glomeruli. The antennal lobe (AL), the first olfactory center in larval Drosophila, is organized in 21 glomeruli. Each AL glomerulus receives innervation from a specific olfactory sensory neuron (OSN), and is therefore identifiable anatomically by the position of the OSN terminal. Olfactory projection neurons (PNs) send a dendrite to a single AL glomerulus and an axon that usually terminates in a single glomerulus in the mushroom body (MB) calyx, a secondary olfactory center, and in the lateral horn. By random labeling of single PNs that express GH146–GAL4, it was previously shown that PNs stereotypically innervate specific AL and calyx glomeruli, and most of these connections have been mapped. Here we report the pattern of innervation of GAL4 lines that drive expression of reporter genes in single or a few PNs, including PNs not identified by the widely used GH146–GAL4 driver. We have mapped the AL and calyx glomeruli innervated by these labeled PNs. This study provides a collection of GAL4 lines to molecularly mark the connections between specific AL and calyx glomeruli. It thus confirms and extends the previous map of AL–calyx connectivity that was based only on randomly labeled single PNs, and provides tools for targeted manipulation of specific PNs for developmental and functional studies.

Section snippets

Screening for projection neuron GAL4 lines

Specific GAL4 lines are an essential tool to study the development, connectivity and function of the nervous system. In the olfactory system of Drosophila the development of PNs that connect the antennal lobe (AL) and higher olfactory centers such as mushroom bodies (MBs) and lateral horn has been studied using the GH146 projection neuron GAL4 line. This line labels about 90 PNs in anterodorsal and lateral clusters of PNs, representing two-thirds of the projection neurons in adults (Jefferis et

Database screening and flies

An image database (Awasaki and Ito, unpublished data) of the NP collection of GAL4 lines (Hayashi et al., 2002) was screened for lines that label the larval AL. Larval brain expression patterns were visualized by crossing GAL4 lines to P{UAS-mCD8::GFP}LL6 (Lee and Luo, 1999) or nSyb::GFP (Ito et al., 1998). Brains were dissected and labeled with antibodies to GFP and Discs-large, as previously described (Masuda-Nakagawa et al., 2005). Secondary antibodies were anti-rabbit Alexa 488 and

Acknowledgements

We acknowledge the Bloomington Drosophila Stock Center for fly stocks, and to the Developmental Studies Hybridoma Bank, University of Iowa, for anti-Discs-large antibody. This work was supported by a grant from the Japan Society for the Promotion of Science to L.M.M.-N.

References (14)

There are more references available in the full text version of this article.

Cited by (11)

  • Odor-taste learning in Drosophila larvae

    2018, Journal of Insect Physiology
    Citation Excerpt :

    In recent decades, light microscopy studies combined with behavioral neurogenetics revealed that larvae receive olfactory stimuli through just 21 olfactory receptor neurons (ORNs) housed in a single sensillum in their head, the dorsal organ (Oppliger et al., 2000; Python and Stocker. 2002; Fishilevich et al., 2005; Kreher et al., 2005). The olfactory information from a given ORN is further conveyed at the larval antennal lobe in a direct one-to-one fashion to 21 projection neurons (PNs) that project to two second-order olfactory brain centers: a) the lateral horn, a brain region thought to organize naïve olfactory behavior and b) the calyx region of the MB, comprised of MB-intrinsic Kenyon cells (KCs), neurons that are required for odor-taste learning and memory (Ramaekers et al., 2005; Masuda-Nakagawa et al., 2010; Masuda-Nakagawa et al., 2009; Thum et al., 2011). Recently, these findings were verified and completed by Berck and coworkers, who reconstructed the larval antennal lobe at synaptic resolution (a connectome of the circuit) using volume electron microscopy (Berck et al., 2016).

  • Immunolocalization of the vesicular acetylcholine transporter in larval and adult Drosophila neurons

    2017, Neuroscience Letters
    Citation Excerpt :

    To our knowledge, this is the first time that VAChT expression has been reported in the nervous system of Drosophila larva. To more clearly determine the areas of VAChT expression in the brain, we used another reporter construct, GH146-Gal4,UAS-GFP (GH146-GFP) that marks projection neurons (PNs), a sub-population of cholinergic neurons [12,19,20]. These neurons maintain their cell body in the olfactory lobe; send dendrites to the antennal lobe, and their axons to the mushroom body and the lateral horn [21,22].

View all citing articles on Scopus
1

Present address: Department of Neurobiology, University of Massachusetts Medical School, Worcester, MA 01605, USA.

View full text