PTTH neuron ablation, through expression of grim^Scer\UAS.cNa under the control of Scer\GAL4^Ptth.cMa, delays puparium formation by about 5 days. The mature mushroom bodies of these flies exhibit γ and α'/β' axonal bundles that are not significantly different in size from those of controls, but their α/β axonal bundles are much thicker, indicating significant expansion of that population. The α/β lobes are already enlarged by 24 hours after puparium formation. Since neuroblast proliferation rate during early metamorphosis is similar to that of wild-type flies, the excess α/β neurons appear to be produced during the prolonged late larval period. This indicates that the sizes of both γ and α/β neuron populations are highly plastic and influenced by organismal growth and development.

Expression of grim^Scer\UAS.cNa under the control of Scer\GAL4^sal.BO results in lethality at the L2/L3 larval transition. The larvae grow normally until the end of the second instar, but are unable to grow further. They survive a few more days, but eventually contract in size before dying between 4 to 5 days after egg deposition. The larvae often have duplicated mouth hooks of L2 and L3 identity, although some complete the L2/L3 transition. The larvae show abnormal feeding behaviour at the late second instar stage, with more than 50% of the larvae straying away food 1 hour after being placed in a small piece of food in the middle of an agar plate.

The tracheal network of animals expressing grim^Scer\UAS.cNa under the control of Scer\GAL4^sal.BO appears normally filled with air at the first larval instar stage. However, at the L2/L3 transition the larvae found outside of the food show a severe defect in air-filling of their tracheal trunks. The tubes are still distinguishable, suggesting that they are present but filled with an aqueous solution. The air-filling failure is seen in the spiracles and main trunks, but only occasionally extends into lateral branches and the tracheoles.

Larvae expressing grim^Scer\UAS.cNa under the control of either Scer\GAL4^sal.BO or Scer\GAL4^desat1.PB and transferred to blue tinted food medium at the L2 or early L3 stage show blue staining of the spiracles that sometimes extends into the main tracheal trunks, indicating a water-tightness defect in the spiracles.

Fat body cells in animals expressing grim^Scer\UAS.cNa under the control of Scer\GAL4^Aug21 undergo precocious and enhanced programmed cell death compared to wild-type fat body cells.

Expression of grim^Scer\UAS.cNa under the control of Scer\GAL4^btl.PU causes gaps in the dorsal trunk as well as disintegration of some of the trachea. When grim^Scer\UAS.cNa is expressed at a higher temperature there is also loss of one of more of the salivary ducts.

Expression of grim^Scer\UAS.cNa under the control of Scer\GAL4^Aug21 results in both sets of salivary glands being either missing or in a state of advanced degeneration by the onset of the third larval instar and all remnants of the corpora allata having disappeared by the onset of wandering.

Larvae expressing grim^Scer\UAS.cNa under the control of Scer\GAL4^Aug21 develop slightly more slowly than their control siblings, pupariating about 8-12 hours later (survival to pupariation does not differ between the mutant and control larvae). The mutant pupae are approximately 75% of the weight of their control siblings, although this size defect is rescued if the animals are fed a diet containing 1ppm juvenile hormone mimic during the third instar.

Pupae expressing grim^Scer\UAS.cNa under the control of Scer\GAL4^Aug21 typically die at around the time of head eversion. Head eversion initiates at the normal time, but the mutants are unable to eject the mouth hooks completely and complete head eversion. Escapers that complete head eversion are not found at 29[o]C, but occur in 20% of cases when white puparia are placed at 18[o]C. If the mutant animals are fed a diet containing 1ppm juvenile hormone mimic during the third instar, 89% continue development beyond head eversion and arrest as pharate adults just before eclosion. These pharate adults have truncated and missing abdominal bristles.

Animals expressing grim^Scer\UAS.cNa under the control of Scer\GAL4^Aug21 show a reduction in proliferation in the outer zone of the optic lobe to about 15% of control values by 8 hours after puparium formation. This reduction in mitotic cells can be rescued by feeding on a diet containing juvenile hormone mimic during the larval stage. Proliferation in the inner proliferation zone of the optic lobe also shows a slight, but significant reduction in the mutant prepupae compared to controls, and this can also be rescued by feeding on a diet containing juvenile hormone mimic.

Prepupae expressing grim^Scer\UAS.cNa under the control of Scer\GAL4^Aug21 show precocious separation of the axons of photoreceptors R7 and R8 in the medulla, showing distinct separation by 6 hours after puparium formation.

All of the Scer\GAL4^Aug21; grim^Scer\UAS.cNa animals die during early pupal life after normal pupariation. Larval development of Scer\GAL4^Aug21; grim^Scer\UAS.cNa animals is delayed and the body weight is reduced. Only about 10% of these pupae undergo successful head eversion. Although the adult organs of these animals initiate development, it is never completed.

Internal portions of pupae expressing Scer\GAL4^Aug21-driven grim^Scer\UAS.cNa appear to retract progressively from the cuticle (apolysis), creating an apparently empty space beginning 6 hours after pupariation. The fat body in the posterior portion of these pupae often appears to be missing. The fat body in pupae expressing Scer\GAL4^Aug21-driven grim^Scer\UAS.cNa undergoes precocious and enhanced programmed cell death and cell dissociation.

Cells of the corpus allatum become ablated as a result of Scer\GAL4^Aug21-driven expression of grim^Scer\UAS.cNa by early wandering third instar larval stage.

jhamt activity is undetectable in wandering third instar larvae expressing grim^Scer\UAS.cNa driven by Scer\GAL4^Aug21.

In vitro juvenile hormone biosynthesis is undetectable in the brain-ring gland complexes of wandering third instar larvae expressing grim^Scer\UAS.cNa driven by Scer\GAL4^Aug21.

Methoprene treatment can rescue the lethality of Scer\GAL4^Aug21-driven expression of grim^Scer\UAS.cNa in larvae, depending on the dose and of methoprene used and the stage of the larvae treated. The rescued adults are reproductively competent.

Expression of grim^Scer\UAS.cNa in the larval hemocytes under the control of Scer\GAL4^He.PZ results in the formation of melanotic aggregates which contain hemocytes.

Larval co-expression of grim^Scer\UAS.cNa with Scer\GAL4^Ptth.cMa results in loss of the prothoracic gland (PG) neurons and reduced survival to adulthood. Surviving females show reduced fecundity, while males exhibit male-on-male courtship behaviours.

As a result of Scer\GAL4^Ptth.cMa-driven grim^Scer\UAS.cNa-expression, wandering third-instar larvae, pupae and adult flies are larger and heavier than wild-type ones. Not only are the bodies of these adults larger and heavier than controls, their wings also show an increase in size due to an increase in cell number. The PG neuron-ablated larvae continue to feed and gain mass for much longer time periods than wild-type controls.

The critical weight for pupariation is increased as a result of Scer\GAL4^Ptth.cMa-driven grim^Scer\UAS.cNa-overexpression.

Scer\GAL4^Ptth.cMa-driven grim^Scer\UAS.cNa-expression causes developmental delays. The duration of each larval instar is lengthened in PG neuron ablated animals compared to controls. Not all PG neuron-ablated animals are able to complete development. Different proportion of the Scer\GAL4^Ptth.cMa-driven grim^Scer\UAS.cNa-expressing animals die at different stages of larval and pupal development. Dead puparia include elongated prepupae, ones with head-eversion defects, and some with other phenotypes characteristic of reduced ecdyson titers.

Larvae expressing Scer\GAL4^Ptth.cMa-driven grim^Scer\UAS.cNa show very low ecdysteroid titers throughout the prolonged third-instar stage. As in wild-type, however, an ecdysteroid peak is evident at the white prepupal stage. 20-hydroxyecdysone(20E)-fed, PG neuron-ablated larvae are able to achieve puparium formation 2.5 days after ecdysis to the third instar, whereas controls lacking 20E feeding do not pupariate until 5-6 days. 20E-feeding also restores adult fertility and abnormal larval, pupal and adult size to that of wild-type.

Expression of grim^Scer\UAS.cNa, under the control of Scer\GAL4^elav-C155, shortens the lifespan of flies.

Expression of grim^Scer\UAS.cNa under the control of Scer\GAL4^Gp150-52A in embryos in the central nervous system midline results in the loss of some midline glia.

Expression of grim^Scer\UAS.cNa under the control of Scer\GAL4^{Obp57e.T:Hsim\VP16} results in a dramatic loss of sensitivity to sucrose in a proboscis extension reflex assay. The flies show reduced sensitivity to sucrose compared to wild type at sucrose concentrations from 10^-6 to 10^-2 M, but no significant difference in sensitivity to sucrose compared to wild type at a sucrose concentration of 10^-1 M.

When grim^Scer\UAS.cNa is driven by Scer\GAL4^rQ286.11, to induce ablation of glial cells, a spectrum of nervous system phenotypes are seen in embryonic hemisegments, which range from having a disrupted CNS and PNS pathways to being essentially normal. grim^Scer\UAS.cNa, Scer\GAL4^rQ286.11 embryos with highly aberrant nervous system patterning correlate with early evidence of glial ablation. From stage 13 onward, when the peripheral glia normally would have migrated into the periphery, the nuclei of the peripheral glial cells in these embryos remain outside the CNS. The peripheral nerves associated with the ablated glia are always defasciculated. In these embryos, sensory axons display a range of errors including stalls, improper fascicle choice, defasciculation, and misguidance on muscle. In glial ablated mutant embryos (driven by Scer\GAL4^rQ286.11 or Scer\GAL4^repo), sensory axons stall in their approach to the CNS. The pioneer motor axons exit the CNS along abnormal trajectories compared to the highly stereotypes pathways observed in wild-type. When grim^Scer\UAS.cNa is driven by Scer\GAL4^rQ14.7, mutant embryos do not show any stalling of sensory neurons. When grim^Scer\UAS.cNa is driven by Scer\GAL4^rQ286.11 or Scer\GAL4^repo, segments that show evidence of glial loss also show sensory stalls at 76% and 85% respectively. Axons cross between the anterior and posterior fascicles in about 50% of hemisegments, or cross the segment boundary at a similar frequency when grim^Scer\UAS.cNa is driven by either Scer\GAL4^rQ286.11 or Scer\GAL4^repo. In grim^Scer\UAS.cNa, Scer\GAL4^rQ286.11 embryos The lch neurites commonly stall at the transition zone and show pathfinding errors as they approach the CNS. Very often the axons head posteriorly and enter the CNS incorrectly toward the posterior fascicle route. The four lch axon projections also show significant defasciculation in some segments. Some sensory neurons migrate to a much lower focal plane in the ventral CNS region than do those in wild-type. In some embryos, lch axons are observed that project along the ventral muscles that lie just beneath the CNS. Also, in the absence of peripheral glia, lch neurons do not consistently migrate along VUM motor neuron tracts, which normally fasciculate with the lch neurons.

When grim^Scer\UAS.cNa is driven by Scer\GAL4^Gp150-52A, embryos typically exhibit a loss of all midline glia most segments of the ventral nerve cord and also exhibit a fusion of several commissural axon bundles.

Scer\GAL4^Aug21, grim^UAS.cNa has lethal | prepupal stage phenotype, suppressible by EcR^RNAi.hs.PL, Scer\GAL4^Aug21

grim^UAS.cNa has increased cell death phenotype, suppressible by Scer\GAL4^Gp150-52A/BacA\p35^UAS.cHa

Scer\GAL4^GMR.PF, grim^UAS.cNa has lethal phenotype, non-suppressible by Diap1^SL, Scer\GAL4^GMR.PF

Scer\GAL4^GMR.PF, grim^UAS.cNa has lethal phenotype, non-suppressible by Diap1^UAS.Tag:HA, Scer\GAL4^GMR.PF

Scer\GAL4^Gp150-52A, grim^UAS.cNa has increased cell death phenotype, non-suppressible by Diap2^UAS.cWa, Scer\GAL4^Gp150-52A

Scer\GAL4^GMR.PF, grim^UAS.cNa has lethal phenotype, non-suppressible by Diap2^UAS.cWa, Scer\GAL4^GMR.PF

Scer\GAL4^Gp150-52A, grim^UAS.cNa has midline glial cell phenotype, enhanceable by Scer\GAL4^Gp150-52A/morgue^EP2367

Scer\GAL4^Gp150-52A, grim^UAS.cNa has midline glial cell phenotype, enhanceable by Scer\GAL4^Gp150-52A/rpr^C.UAS

Scer\GAL4^Gp150-52A, grim^UAS.cNa has midline glial cell phenotype, enhanceable by Scer\GAL4^Gp150-52A/rpr^UAS.cZa

Scer\GAL4^Gp150-52A, grim^UAS.cNa has midline glial cell phenotype, enhanceable by hid^UAS.cZa/Scer\GAL4^Gp150-52A

Scer\GAL4^He.PZ, grim^UAS.cNa has embryonic/larval hemolymph | third instar larval stage phenotype, suppressible by Spn27A^UAS.cLa/Scer\GAL4^He.PZ

Scer\GAL4^Gp150-52A, grim^UAS.cNa has ventral midline of embryo phenotype, suppressible by Diap1^UAS.Tag:HA, Scer\GAL4^Gp150-52A

grim^UAS.cNa has midline glial cell phenotype, suppressible by Scer\GAL4^Gp150-52A/BacA\p35^UAS.cHa

grim^UAS.cNa/Scer\GAL4^Gp150-52A is an enhancer of midline glial cell phenotype of Scer\GAL4^Gp150-52A, rpr^C.UAS

grim^UAS.cNa/Scer\GAL4^Gp150-52A is an enhancer of midline glial cell phenotype of Scer\GAL4^GMR.PF, rpr^UAS.cZa

grim^UAS.cNa/Scer\GAL4^Gp150-52A is an enhancer of midline glial cell phenotype of Scer\GAL4^Gp150-52A, hid^UAS.cZa