1159 bp deletion resulting from the imprecise excision of P{GSV1}GSd033GSd033, which removes mir-310, mir-311, mmir-313, and mir-314.
Df(2R)KT40 contains an 1159 bp deletion.
Df(2R)KT40/Df(2R)Exel6070 transheterozygotes show excessive or disorganized basal stalk cells, mis-shaped follicle cells, a multilayered follicular epithelium and/or aberrant nurse cell number, as compared to controls; the multilayering is virtually absent under starvation conditions. Under starvation, these transheterozygotes show a significant increase in the mitotic index of the follicular epithelium, as compared to controls.
The aforementioned defects are strongly rescued by the adulthood-only expression of either hhHMS00492 or Rab23JF02859 under the control of Scer\GAL4bab1-Pgal4-2 (and Gal80[ts] for temporal control of expression).
Df(2R)KT40/Df(2R)Exel6070 mutant brains contain an increased number of M-phase neuroblasts per lobe compared to controls.
Df(2R)Exel6070/Df(2R)KT40 mutants do not display any abnormalities in the gross morphology of synapses or in the number of synaptic boutons and branch points per muscle surface area at muscle 4 and muscle 6/7 neuromuscular junctions compared to heterozygous controls.
Heterozygosity for Df(2R)Exel6285 results in a significant reduction in evoked excitatory junctional potentials (EJPs) and quantal content (QC) recorded from muscles of homozygous Df(2R)KT40 mutant larvae.
Homozygosity for Df(2R)KT40 can lead to an enhancement of calcium influx at the larval neuromuscular junction.
Homozygous Df(2R)KT40 mutant larvae show a higher sensitivity to increasing extracellular concentration of Ca[2+] compared with wild-type. The Ca[2+] channel blocker Ni[2+] reduces both EJPs and QC significantly more in Df(2R)KT40 mutants compared with wild-type.
Df(2R)KT40 homozygotes show a significantly enlarged crop under ad libitum nutrition, as compared to controls; individuals also show a significant decrease in egg laying under both ad libitum and starvation conditions, as compared to controls.
Homozygous Df(2R)KT40 mutant optic lobes contain neurons with premature axon stops.
The brains of Df(2R)KT40 mutants exhibit a weak 'cobblestone-like' phenotype; dense cellular masses (lumps) are seen that overgrow the normal brain contour, protruding above the neural lamina.
Df(2R)KT40 mutant brains contain an increased number of M-phase neuroblasts per lobe compared to controls.
Homozygous Df(2R)KT40 mutants are viable and fertile.
Electrophysiological analysis reveals a significant increase in the size of evoked excitatory junctional potentials (EJPs) in homozygous Df(2R)KT40 larvae, with no associated change in muscle membrane potential or defect in Ca[2+] cooperativity. There is a dramatic increase in the average amplitude evoked excitatory junctional potential currents (EJCs), however, the size of miniature EJCs (mEJC) is unaffected. This results in a significant increase in quantal content (QC).
Neuromuscular junctions of homozygous Df(2R)KT40 mutant larvae display ultrastructural abnormalities: the number of T-bars is increased. In addition, there is a mild increase in the number of large synaptic vesicles in Df(2R)KT40 mutants, but these large vesicles are present in less than 40% of the synapses.
