Insertion of a 1.6kb P-element.
meiotic cell cycle & spindle | male
neuroblast & centrosome & larva
Homozygous and hemizygous males die before reaching the third larval instar stage. The testes of polo1/polo2 males show cytological abnormalities during all stages of spermatogenesis. Primary spermatocytes containing less than the wild-type number of 16 cells (usually containing 14 cells of normal size and 1 large cell) are seen. The overall organisation of the spindles of metaphase I cysts is defective; the spindles appear shorter and thicker than wild-type, showing large asters of microtubule bundles. Metaphase II cysts have similar abnormalities. Cysts in the second meiotic division are mostly incomplete and highly disorganised. Onion stage cysts contain a variable number of cells, with variable nuclear and Nebenkern volume.
Homozygous larval neuroblasts have smaller centrosomes than normal.
Karess.
All fully viable and fertile revertants of polo2 obtained in a screen were associated with the loss of the P-element that is inserted at 77A3 in polo2.