Imprecise excision of the P{lacW}barrk14014 insertion resulting in a deletion of the promoter and start of the open reading frame of both lok and barr genes.
mitosis & nuclear chromosome & embryo
Only 20.1 +/- 1.9% of embryos derived from lokE51 females mated to wild-type males hatch. Only 13.0 +/- 0.2% of embryos derived from lokE51 females mated to lokE51 males hatch. 61.5 +/- 1.1% of embryos derived from lokE51 females have abnormal nuclei of variable sizes. These defects can be seen as early as nuclear cycle 10. The large nuclei remain at the cortex of the embryos and are usually surrounded by areas that lack normal nuclei. Two or more spindles and multiple centrosomes are observed around the abnormal nuclei. Chromosomes from the abnormal nuclei do not separate during anaphase. 92% of embryos derived from lokE51 females show abnormal nuclei when treated with 100rad γ-irradiation (in contrast to 4% of wild-type embryos treated with the same dose of irradiation).
Homozygotes for Df(2L)E51 (which causes both lokE51 and barrE51), in which barr function has been rescued using barr+tXa, show increased radiation sensitivity and genomic instability compared to wild type; larval or pupal lethality is significantly higher after irradiation compared to heterozygous controls and mutants show a much higher rate of loss of heterozygosity (LOH) both with or without irradiation. No significant increase in apoptosis is seen in mutant wing discs in response to X-ray irradiation (in contrast to wild-type wing discs which show a significant increase in apoptosis after irradiation). There are significant numbers of mitotic cells in mutant irradiated wing discs (in contrast to wild type), although there are fewer mitotic cells than in untreated mutant wing discs.
lok[+]/lokE51 is a non-enhancer of visible | adult stage phenotype of Hsap\MAPTUAS.cWa, Scer\GAL4GMR.PF
lokE51 has nucleus | embryonic stage phenotype, suppressible by stgunspecified/stg[+]
lokE51 has nucleus | embryonic stage phenotype, suppressible by polo[+]/polo1
lok[+]/lokE51 is a non-enhancer of eye phenotype of Hsap\MAPTUAS.cWa, Scer\GAL4GMR.PF
The fraction of embryos derived from lokE51 females which have abnormal nuclei is reduced (from 61.5 +/- 1.1%) if the females also carry one copy of polo1 (to 27.0 +/- 3.2% of embryos) or one copy of stgunspecified (to 38.5 +/- 7.0% of embryos). The fraction of embryos derived from lokE51 females which have abnormal nuclei (61.5 +/- 1.1%) is only slightly altered (to 52.2 +/- 1.6%) if the females also carry one copy of CycAunspecified.
One copy of lokE51 does not modify the retinal degeneration seen when Hsap\MAPTScer\UAS.cWa is expressed under the control of Scer\GAL4GMR.PF.
