Time-lapse video microscopy of living Drosophilaspermatocytes reveals the relationship between different components of the cell division machinery and the spindle checkpoint. E. Rebollo , H. Varmark , C. Gonzalez. Cell Biol & Biophysics, EMBL/Gonzalez's Lab, Heidelberg, Germany.

   The spindle checkpoint guards against chromosome segregation errors by delaying the onset of anaphase in cells whose spindles are defective. We have previously shown that Drosophila primary spermatocytes have a spindle checkpoint that can be activated in several conditions including treatment with colchicine, a microtubule depolymerising drug (EMBO Reports 2000,vol 11, no 11, pp 65-70). More recently, it has been shown that the two kinetochore components rod and zw10 are required for the function of this checkpoint (Nat.Cell.Biol. 2000, vol 2, pp 948-952) that can also be activated with taxol, a microtubule stabilizing drug. To further characterise the spindle checkpoint of these cells, we are studying by real-time microscopy of live spermatocytes a collection of mutants that disrupt male meiosis at different stages . The specific aims of this project are twofold. Firstly, to determine which mutant phenotypes bring about the activation of the spindle checkpoint. Secondly, to identify those mutants which inhibit the activation of the checkpoint that is normally triggered by taxol or colchicine treatment. From these data we hope to be able to define the alterations of the meiotic apparatus the spindle checkpoint is able to detect as well as those defects of the apparatus that prevent the activation of the checkpoint.