karyosome & oocyte
spindle microtubule & larval brain
spindle microtubule & oocyte
spindle pole & larval brain
spindle pole & oocyte
Homozygous females show elevated levels of chromosome nondisjunction of the X chromosome (9.8%). 2nd chromosome nondisjunction is elevated in homozygous females. Nondisjunction of the X and 2nd chromosomes occurs predominantly at meiosis I.
Homozygous females show similar crossing over of the X chromosome as control females.
Mutant males do not show X chromosome nondisjunction.
X chromosome nondisjunction is increased to 16.4% in homozygous XXY females, with only 66% of the events involving the two X chromosomes segregating from the Y.
42% of oocytes show disorganisation of the chromosomes within the karyosome in homozygous females. In most of these (33%), the karyosome is disorganised and the chromosomes are unevenly distributed in the centre of the spindle. The oocytes also show spindle defects; 4% have frayed spindles, 17% of spindles are monopolar, 21% lack tapering at the pole and 21% show a reduction of microtubules between the poles.
Mitotically dividing brain cells of mutant larvae do not show an increase in aneuploidy or precocious sister chromatid separation compared to control cells. Spindle defects are seen in some of the mutant mitotic cells; cells with a single pole, three poles, abnormal spindle morphology or a gap between the pole and spindle microtubules are seen.
mei-381 mei-2187/mei-381 mei-2181 females show elevated levels of chromosome nondisjunction of the X (43.5%) and 4th (17.0%) chromosomes.
mei-381 noda double mutant females show an additive phenotype for chromosome nondisjunction; the frequency of X chromosome nondisjunction (8.9%) is similar to that of mei-381 single mutants and the frequency of 4th chromosome nondisjunction (71.4%) is similar to that of noda single mutants.
mei-381 ; ald1/aldC3 double mutant females show 20.9% nondisjunction of the X chromosome.
mei-381 ; ald1/aldC3 double mutant females show spindle defects in the oocyte, with no spindles appearing normal; 17% have frayed spindles, 43% of spindles are monopolar, 37% lack tapering at the pole and 27% show a reduction of microtubules between the poles.
Expression of either Rab27LP.Scer\UAS.P\T.T:Ivir\HA1 or Rab27GH.Scer\UAS.P\T.T:Ivir\HA1 under the control of Scer\GAL4nos.UTR.T:Hsim\VP16 does not rescue the mei-381 nondisjunction phenotype.
mei-381 is rescued by mei-38UASp.Tag:HA/Scer\GAL4VP16.nanos.UTR
Baker and Carpenter
The mei-381 chromosome contains two closely linked deletions, which affect the coding region of CG14781 and one of the two isoforms of Rab27. Complementation analysis with different mutations that affect CG14781 and/or Rab27 and rescue experiments show that the meiotic nondisjunction phenotype associated with the mei-381 chromosome is due to an effect on CG14781 and thus CG14781 corresponds to mei-38.
Rab27J20-2 complements mei-381.