Frizzled regulates localization of cell-fate determinants and mitotic spindle rotation during asymmetric cell division.
Cell-fate diversity is generated in part by the unequal segregation of cell-fate determinants during asymmetric cell divisions. In the Drosophila pupa, the pI sense organ precursor cell is polarized along the anterior-posterior axis of the fly and divides asymmetrically to generate a posterior pIIa cell and an anterior pIIb cell. The anterior pIIb cell specifically inherits the determinant Numb and the adaptor protein Partner of Numb (Pon). By labelling both the Pon crescent and the microtubules in living pupae, we show that determinants localize at the anterior cortex before mitotic-spindle formation, and that the spindle forms with random orientation and rotates to line up with the Pon crescent. By imaging living frizzled (fz) mutant pupae we show that Fz regulates the orientation of the polarity axis of pI, the initiation of spindle rotation and the unequal partitioning of determinants. We conclude that Fz participates in establishing the polarity of pI.
Bellaïche
Y
Y
Ecole Normale Supérieure, UMR 8544, 46, rue d'Ulm, 75230 Paris Cedex 05, France.
Gho
M
M
Kaltschmidt
J A
JA
Brand
A H
AH
Schweisguth
F
F
D000818:Animals; D019521:Body Patterning / Q000235:genetics*; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D002455:Cell Division / Q000235:genetics*; D019070:Cell Lineage / Q000235:genetics*; D016764:Cell Polarity / Q000235:genetics*; D018385:Centrosome / Q000378:metabolism; D004330:Drosophila / Q000166:cytology / Q000254:growth & development* / Q000378:metabolism; D029721:Drosophila Proteins; D051157:Frizzled Receptors; D049452:Green Fluorescent Proteins; D007202:Indicators and Reagents / Q000032:analysis; D007605:Juvenile Hormones / Q000235:genetics / Q000378:metabolism; D008164:Luminescent Proteins / Q000032:analysis; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D008870:Microtubules / Q000235:genetics / Q000378:metabolism; D009475:Neurons, Afferent / Q000166:cytology / Q000378:metabolism; D011418:Prophase / Q000235:genetics; D011679:Pupa / Q000166:cytology / Q000254:growth & development / Q000378:metabolism; D043562:Receptors, G-Protein-Coupled; D012399:Rotation; D012679:Sense Organs / Q000166:cytology / Q000254:growth & development / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics; D008941:Spindle Apparatus / Q000235:genetics*
D002352:Carrier Proteins; D029721:Drosophila Proteins; D051157:Frizzled Receptors; D007202:Indicators and Reagents; D007605:Juvenile Hormones; D008164:Luminescent Proteins; D008565:Membrane Proteins; C115164:PON protein, Drosophila; D043562:Receptors, G-Protein-Coupled; C058784:fz protein, Drosophila; C060606:numb protein, Drosophila; D049452:Green Fluorescent Proteins