|Feature type||allele||Associated gene||Dmel\mr|
|Map ( GBrowse )|
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|Nature of the Allele|
|Mutations Mapped to the Genome|
|Associated Sequence Data|
|Nature of the lesion|
Amino acid replacement: W739R.
|Phenotype Manifest In|
nurse cell & nuclear chromosome
nurse cell & nucleus
The nurse cells revert to mitosis at stage 5 in mr1/mr2 egg chambers. Nurse cells in later mr1/mr2 egg chambers often become pycnotic. Embryos derived from mr1/mr2 egg chambers which complete oogenesis complete meiosis, however, the zygotic nuclei and frequently the polar bodies, are arrested on metaphase spindles that are anastral or have broad poles. The chromosomes are hypercondensed in these embryos.
Semi-lethal when hemizygous, with most hemizygotes dying as pharate adults. Escapers have etched tergites and very rough eyes. Nurse cells in homozygous ovaries initiate endo cycles, but later egg chambers contain condensed chromosomes in place of polyploid nurse cell nuclei. These condensed chromosomes are associated with large multipolar spindles. Ring canals are seen to degenerate shortly after the inappropriate spindles are seen. The nurse cell defects are not visible until stage 4 of egg chamber development. The follicle cell epithelium sometimes forms a double layer of cells. Homozygous or mr1/mr2 females sometimes lay eggs (which do not hatch). Fertilised eggs show an early metaphase arrest phenotype, containing usually between 6 and 10 metaphase nuclei. The spindles are broader than wild-type both at the metaphase plate and at the spindle poles. Metaphase spindles are found at the position where the polar bodies are normally located.
Less extreme than mr. Nearly wild type at 19oC. female-sterile Oogenesis normal through stage 4; then compound nurse cell chromosomes fall apart and degenerate. Karyosome of oocyte also disappears. Oogenesis does not proceed beyond sixth stage (King, 1964). RK2 at 25oC or above.
|Phenotype Manifest In|
lmgA mr double mutants die at prepupal stage P4(ii). The mitotic index in third larval instar brains is increased compared to wild type and 31.8 +/- 3.9 % of the cells are polyploid. Third larval instar brains and wing imaginal discs show increased levels of apoptosis compared to wild type.
mr/mr enhances the loss of germline stem cells that is seen in eff/eff[mer1] females, such that the rate of germline stem cell loss is more rapid in the double mutant females.
|Complementation & Rescue Data|
|Stocks ( 3 )|
|Notes on Origin|
Bridges, 24th Nov. 1925.
|External Crossreferences & Linkouts|
|Synonyms & Secondary IDs ( 2 )|
|Secondary FlyBase IDs|
|References ( 8 )|