Drosophila GABAergic systems II. Mutational analysis of chromosomal segment 64AB, a region containing the glutamic acid decarboxylase gene

Abstract

The Drosophila melanogaster Gad gene maps to region 64A3-5 of chromosome 3L and encodes glutamic acid decarboxylase (GAD), the rate-limiting enzyme for the synthesis of the inhibitory neurotransmitter gamma-aminobutyric acid (GABA). Because this neurotransmitter has been implicated in developmental functions, we have begun to study the role of GABA synthesis during Drosophila embryogenesis. We show that Gad mRNA is expressed in a widespread pattern within the embryonic nervous system. Similarly, GAD-immunoreactive protein is present during embryogenesis. These results prompted us to screen for embryonic lethal mutations that affect GAD activity. The chromosomal region to which Gad maps, however, has not been subjected to an extensive mutational analysis, even though it contains several genes encoding important neurobiological, developmental, or cellular functions. Therefore, we have initially generated both chromosomal rearrangements and point mutations that map to the Drosophila 64AB interval. Altogether, a total of 33 rearrangements and putative point mutations were identified within region 64A3-5 to 64B12. Genetic complementation analysis suggests that this cytogenetic interval contains a minimum of 19 essential genes. Within our collection of lethal mutations are several chromosomal rearrangements, two of which are in the vicinity of the Gad locus. One of these rearrangements, Df(3L)C175, is a small deletion that removes the Gad locus and at least two essential genes; the second, T(2;3)F10, is a reciprocal translocation involving the second and third chromosomes with a break within region 64A3-5. Both of these rearrangements are associated with embryonic lethality and decreased GAD enzymatic activity.

ACK Family Tyrosine Kinase Activity Is a Component of Dcdc42 Signaling during Dorsal Closure inDrosophila melanogaster

“…2A) revealed that DACK is removed by the deficiency Df(3L)C175, mapping it to 64A3-64A5. The 64A region has been well characterized genetically and it is likely that most of the essential genes have been found (30,41). Five lethal complementation groups have been identified which are removed by Df(3L)C175, with all being represented by at least six alleles, except for l(3)64Am, which has one allele (Fig.…”

GABAergic modulation of motor‐driven behaviors in juvenileDrosophilaand evidence for a nonbehavioral role for GABA transport

“…However, the major components of GABAergic systems have been detected throughout most stages of Drosophila development by both immunocytochemical and molecular analyses. mRNA transcripts for glutamic acid decarboxylase (GAD), the synthetic enzyme for GABA, were detected in the CNS of embryos, larvae, pupae, and adults (Jackson et al, 1990) and a GAD-immunoreactive protein was also detected in neuronal tissues during embryogenesis (Kulkarni et al, 1994). Immunocytochemical analyses detected the Drosophila GABA receptor subunit Rdl in the CNS of embryos and throughout the adult brain as well as within the ellipsoid body of the adult CC (Aronstein and Ffrench-Constant, 1995;Harrison et al, 1996).…”

dbxmediates neuronal specification and differentiation through cross-repressive, lineage-specific interactions witheveandhb9

“…1H; data not shown). Immunofluorescent and immunohistochemical stainings were performed as described by Patel (Patel, 1994), using the following antibodies: Guinea pig anti-Dbx (1:1500), rabbit anti-vGlut [1:5000 (Daniels et al, 2004)]; rabbit anti-Eve [1:3000 (Frasch et al, 1987)], rabbit and guinea pig anti-Hb9 (1:1500), rabbit anti-GAD [1:1000 (Kulkarni et al, 1994)], and rabbit anti-GFP (1:1000, Torey Pines). Monoclonal antibodies (obtained from the Developmental Studies Hybridoma Bank, Iowa): 9E10 (Myc 1:10,), 1D4 (FasII; 1:10), BP102 (1:10), 4D9 (engrailed/invected; 1:10), 7E8A10 (ELAV; 1:10).…”