The commonly used eye-specific sev-GAL4 and GMR-GAL4 drivers in Drosophila melanogaster are expressed in tissues other than eyes also

Abstract

The binary GAL4-UAS system of conditional gene expression is widely used by Drosophila geneticists to target expression of the desired transgene in tissue of interest. In many studies, a preferred target tissue is the Drosophila eye, for which the sev-GAL4 and GMR-GAL4 drivers are most widely used since they are believed to be expressed exclusively in the developing eye cells. However, several reports have noted lethality following expression of certain transgenes under these GAL4 drivers notwithstanding the fact that eye is not essential for survival of the fly. Therefore, to explore the possibility that these drivers may also be active in tissues other than eye, we examined the expression of UAS-GFP reporter driven by the sev-GAL4 or GMR-GAL4 drivers. We found that both these drivers are indeed expressed in additional tissues, including a common set of specific neuronal cells in larval and pupal ventral and cerebral ganglia. Neither sev nor glass gene has so far been reported to be expressed in these neuronal cells. Expression pattern of sev-GAL4 driver parallels that of the endogenous Sevenless protein. In addition to cells in which sev-GAL4 is expressed, the GMR-GAL4 is expressed in several other larval cell types also. Further, two different GMR-GAL4 lines also show some specific differences in their expression domains outside the eye discs. These findings emphasize the need for a careful confirmation of the expression domains of a GAL4 driver being used in a given study, rather than relying only on the empirically claimed expression domains.

Regulatory Role of RNA Chaperone TDP-43 for RNA Misfolding and Repeat-Associated Translation in SCA31

“…A pupal lethal line (L line, line #4) had the highest level of UGGAA exp expression among the SCA31 fly lines, revealed by quantitative reverse-transcription PCR (RT-PCR) (Figure 1G). Given that the GMR-GAL4 driver is reported to be expressed in additional tissues including larval wing imaginal disc and neuronal cells in larval ventral and cerebral ganglia, besides eye imaginal disc, the leaky expression of UGGAA exp RNA in these tissues may be a cause of the pupal lethality (Ray and Lakhotia, 2015). …”

Dual Roles of O-Glucose Glycans Redundant with Monosaccharide O-Fucose on Notch in Notch Trafficking

“…The following UAS lines were used for RNA interference (RNAi): UAS-Notch inverted repeat (21) and UAS-peptide O-xylosyltransferase (Oxt) inverted repeat (21). As lines expressing Gal4 specifically in the dorsal side of the wing disc, posterior side of wing disc, eye, and bristles on the dorsal head capsule, apterous (ap)-Ga4 (23), hedgehog (hh)-Gal4 (24), GMR-Gal4 (25), and scabrous (sca)-Gal4 (26) were used, respectively.…”

Activated Ras/JNK driven Dilp8 in imaginal discs adversely affects organismal homeostasis during early pupal stage in Drosophila, a new checkpoint for development

“…Further, the Malpighian tubules (MT), which become abdominal by 12 to 14 hours APF in wild type as well as sev‐GAL4 > UAS‐Ras1 V12 pupae (arrows in Figure A,B), did not retract but persisted in anterior part in GMR‐GAL4 > UAS‐Ras1 V12 and sev‐GAL4 > UAS‐Ras1 V12 hsrω‐RNAi pupae (arrows in Figure C,D). The characteristic metamorphic changes causing compaction of cells in MT (Figure E,F), histolysis of SG (Figure H,I), and disappearance of the posterior seven pairs of abdominal segmental dorsomedian sev‐GAL4 > UAS ‐ GFP expressing neurons (Figure N,Q) seen in sev‐GAL4 > UAS‐GFP (similar to that in wild type) and sev‐GAL4 > UAS‐Ras1 V12 24‐ to 25‐hour‐old pupae, did not occur in the early dying 24‐ to 25‐hour‐old sev‐GAL4 > UAS‐Ras1 V12 hsrω‐RNAi pupae. They continued to show these structures as in 8‐ to 9‐hour‐old pupae even at 24 to 25 hours APF (Figure G,J,M,P).…”

“…Pupal age, except in K‐M, is 24 to 25 hours APF; in K‐M the pupal age is 8 to 9 hours APF; cross is marked in H and I since the SG is already histolysed and thus not visible in pupae of these genotypes at 24 to 25 hours APF. The sev‐GAL4 > GFP expressing (white) segmentally arranged dorsomedian pairs of neurons in the abdominal A1 to A7 neuromeres of VG at 8 to 9 hours are marked as a1‐a7 in K‐M and pointed by arrows in P (24‐25 hours APF) stage in genotypes noted above the columns; arrows in N and Q indicate the persisting sev‐GAL4 > GFP expression in the anterior‐most (t3 in T3 neuromere) dorsomedian paired neurons . Scale bar in F denotes 50 μm and applies to E‐P.…”