Tools for neuroanatomy and neurogenetics in Drosophila. Proc Natl Acad Sci

Janelia Farm Research Campus, Howard Hughes Medical Institute, Ashburn VA 20147, USA.
Proceedings of the National Academy of Sciences (Impact Factor: 9.67). 07/2008; 105(28):9715-20. DOI: 10.1073/pnas.0803697105
Source: PubMed


We demonstrate the feasibility of generating thousands of transgenic Drosophila melanogaster lines in which the expression of an exogenous gene is reproducibly directed to distinct small subsets of cells in the adult brain. We expect the expression patterns produced by the collection of 5,000 lines that we are currently generating to encompass all neurons in the brain in a variety of intersecting patterns. Overlapping 3-kb DNA fragments from the flanking noncoding and intronic regions of genes thought to have patterned expression in the adult brain were inserted into a defined genomic location by site-specific recombination. These fragments were then assayed for their ability to function as transcriptional enhancers in conjunction with a synthetic core promoter designed to work with a wide variety of enhancer types. An analysis of 44 fragments from four genes found that >80% drive expression patterns in the brain; the observed patterns were, on average, comprised of <100 cells. Our results suggest that the D. melanogaster genome contains >50,000 enhancers and that multiple enhancers drive distinct subsets of expression of a gene in each tissue and developmental stage. We expect that these lines will be valuable tools for neuroanatomy as well as for the elucidation of neuronal circuits and information flow in the fly brain.

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Available from: Kenneth H Wan, Oct 01, 2015
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    • "In the case of five out of eight of the identified enhancers, multiple constructs inserted in at least two distinct genomic locations were tested for activity. For the whole gene surveys, with the exception of upd, we used lines from the Rubin GAL4 collection (Jenett et al., 2012; Pfeiffer et al., 2008), in which non-coding sequences are fused to the GAL4 transcription factor and inserted into the attP2 site on the third chromosome. We supplemented these searches with constructs we generated (see Transgenic Constructs) when necessary. "
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    Developmental Cell 09/2015; DOI:10.1016/j.devcel.2015.08.005 · 9.71 Impact Factor
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    • "This system allows in vivo repurposing of gene expression patterns through genetic crossing schemes to switch between binary systems (Gal4, LexA, Q) or to achieve intersection by introducing Gal80 or Split-Gal4 hemi-drivers (Gohl et al. 2011) the minimal number of cells required for a behavior may be inhibited by the lack of enhancer-trap expression patterns with sufficiently restricted patterns to be informative for mapping. It may require the combination of a collection of enhancer-trap or promoter-driven Gal4 lines and ET-FLP lines to produce smaller intersection patterns (Pfeiffer et al. 2008; Jenett et al. 2012). Third, the number of ET-FLPx2 lines currently available most likely limits the power of the FINGR system. "
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    • "The A hemilineage is downstream of Notch activation , whereas the B hemilineage is downstream of Notch inactivation . It appears that the 3 Kb average size of the CRM (Pfeiffer et al., 2008) is too small for both pathways to be able to readily act independently of each other. "
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    ABSTRACT: We report the larval CNS expression patterns for 6,650 GAL4 lines based on cis-regulatory regions (CRMs) from the Drosophila genome. Adult CNS expression patterns were previously reported for this collection, thereby providing a unique resource for determining the origins of adult cells. An illustrative example re-veals the origin of the astrocyte-like glia of the ven-tral CNS. Besides larval neurons and glia, the larval CNS contains scattered lineages of immature, adult-specific neurons. Comparison of lineage expression within this large collection of CRMs provides insight into the codes used for designating neuronal types. The CRMs encode both dense and sparse patterns of lineage expression. There is little correlation be-tween brain and thoracic lineages in patterns of sparse expression, but expression in the two regions is highly correlated in the dense mode. The optic lobes, by comparison, appear to use a different set of genetic instructions in their development.
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