The GC kinase Fray and Mo25 regulate Drosophila asymmetric divisions.
Drosophila neuroblasts provide an excellent model for asymmetric cell divisions, where cell-fate determinants such as Miranda localize at the basal cortex and segregate to one daughter cell. Mechanisms underlying this process, however, remain elusive. We found that Mo25 and the GC kinase Fray act in this regulation. mo25 and fray mutants show an indistinguishable defect in Miranda localization. On the other hand, Drosophila Mo25 interacts with the tumor suppressor kinase Lkb1 in vivo, as have shown in mammals. Overexpression of Lkb1, which accumulates in the cell cortex, drastically relocalizes both Mo25 and Fray from the cytoplasm to the cortex, causing the same phenotype as mo25-mutant neuroblasts. Recovery from this defect caused by Lkb1 overexpression requires simultaneous overexpression of Mo25 and Fray. We suggest from those results that Mo25 and Fray operate together or in the same pathway in Drosophila asymmetric processes, and that their function counterbalances Lkb1.
Laboratory for Cell Asymmetry, Center for Developmental Biology, RIKEN, 2-2-3 Minatojima-Minamimachi, Chuou-ku, Kobe 650-0047, Japan.
Yoshihiro
Y
Yamamoto
Yasushi
Y
Izumi
Fumio
F
Matsuzaki
D000818:Animals; D019521:Body Patterning / Q000502:physiology*; D002455:Cell Division / Q000502:physiology; D002478:Cells, Cultured; D029721:Drosophila Proteins / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000196:embryology* / Q000502:physiology*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*
D029721:Drosophila Proteins; C100024:Mo25 protein, Drosophila; D017346:Protein Serine-Threonine Kinases; C526279:fray protein, Drosophila