TY - JOUR
T1 - Live imaging of Drosophila brain neuroblasts reveals a role for Lis1/dynactin in spindle assembly and mitotic checkpoint control
AU - Siller, Karsten H.
AU - Serr, Madeline
AU - Steward, Ruth
AU - Hays, Tom S.
AU - Doe, Chris Q.
PY - 2005/11
Y1 - 2005/11
N2 - Lis1 is required for nuclear migration in fungi, cell cycle progression in mammals, and the formation of a folded cerebral cortex in humans. Lis1 binds dynactin and the dynein motor complex, but the role of Lis1 in many dynein/dynactin-dependent processes is not clearly understood. Here we generate and/or characterize mutants for Drosophila Lis1 and a dynactin subunit, Glued, to investigate the role of Lis1/dynactin in mitotic checkpoint function. In addition, we develop an improved time-lapse video microscopy technique that allows live imaging of GFP-Lis1, GFP-Rod checkpoint protein, green fluorescent protein (GFP)-labeled chromosomes, or GFP-labeled mitotic spindle dynamics in neuroblasts within whole larval brain explants. Our mutant analyses show that Lis1/dynactin have at least two independent functions during mitosis: first promoting centrosome separation and bipolar spindle assembly during prophase/prometaphase, and subsequently generating interkinetochore tension and transporting checkpoint proteins off kinetochores during metaphase, thus promoting timely anaphase onset. Furthermore, we show that Lis1/dynactin/dynein physically associate and colocalize on centrosomes, spindle MTs, and kinetochores, and that regulation of Lis1/dynactin kinetochore localization in Drosophila differs from both Caenorhabditis elegans and mammals. We conclude that Lis1/dynactin act together to regulate multiple, independent functions in mitotic cells, including spindle formation and cell cycle checkpoint release.
AB - Lis1 is required for nuclear migration in fungi, cell cycle progression in mammals, and the formation of a folded cerebral cortex in humans. Lis1 binds dynactin and the dynein motor complex, but the role of Lis1 in many dynein/dynactin-dependent processes is not clearly understood. Here we generate and/or characterize mutants for Drosophila Lis1 and a dynactin subunit, Glued, to investigate the role of Lis1/dynactin in mitotic checkpoint function. In addition, we develop an improved time-lapse video microscopy technique that allows live imaging of GFP-Lis1, GFP-Rod checkpoint protein, green fluorescent protein (GFP)-labeled chromosomes, or GFP-labeled mitotic spindle dynamics in neuroblasts within whole larval brain explants. Our mutant analyses show that Lis1/dynactin have at least two independent functions during mitosis: first promoting centrosome separation and bipolar spindle assembly during prophase/prometaphase, and subsequently generating interkinetochore tension and transporting checkpoint proteins off kinetochores during metaphase, thus promoting timely anaphase onset. Furthermore, we show that Lis1/dynactin/dynein physically associate and colocalize on centrosomes, spindle MTs, and kinetochores, and that regulation of Lis1/dynactin kinetochore localization in Drosophila differs from both Caenorhabditis elegans and mammals. We conclude that Lis1/dynactin act together to regulate multiple, independent functions in mitotic cells, including spindle formation and cell cycle checkpoint release.
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U2 - 10.1091/mbc.E05-04-0338
DO - 10.1091/mbc.E05-04-0338
M3 - Article
C2 - 16107559
AN - SCOPUS:27644445239
SN - 1059-1524
VL - 16
SP - 5127
EP - 5140
JO - Molecular biology of the cell
JF - Molecular biology of the cell
IS - 11
ER -