Two types of asymmetric divisions in the Drosophila sensory organ precursor cell lineage.
Asymmetric partitioning of cell-fate determinants during development requires coordinating the positioning of these determinants with orientation of the mitotic spindle. In the Drosophila peripheral nervous system, sensory organ progenitor cells (SOPs) undergo several rounds of division to produce five cells that give rise to a complete sensory organ. Here we have observed the asymmetric divisions that give rise to these cells in the developing pupae using green fluorescent protein fusion proteins. We find that spindle orientation and determinant localization are tightly coordinated at each division. Furthermore, we find that two types of asymmetric divisions exist within the sensory organ precursor cell lineage: the anterior-posterior pI cell-type division, where the spindle remains symmetric throughout mitosis, and the strikingly neuroblast-like apical-basal division of the pIIb cell, where the spindle exhibits a strong asymmetry at anaphase. In both these divisions, the spindle reorientates to position itself perpendicular to the region of the cortex containing the determinant. On the basis of these observations, we propose that two distinct mechanisms for controlling asymmetric cell divisions occur within the same lineage in the developing peripheral nervous system in Drosophila.
Roegiers
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Howard Hughes Medical Institute, Departments of Physiology and Biochemistry, University of California, San Francisco, California 94143-0725, USA.
Younger-Shepherd
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D000818:Animals; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D002455:Cell Division / Q000235:genetics*; D019070:Cell Lineage / Q000235:genetics*; D016764:Cell Polarity / Q000235:genetics; D003598:Cytoskeletal Proteins / Q000235:genetics / Q000378:metabolism; D004330:Drosophila / Q000166:cytology / Q000254:growth & development* / Q000378:metabolism; D029721:Drosophila Proteins; D051157:Frizzled Receptors; D018507:Gene Expression Regulation, Developmental; D049452:Green Fluorescent Proteins; D007202:Indicators and Reagents / Q000032:analysis; D007399:Interphase / Q000235:genetics; D007605:Juvenile Hormones / Q000235:genetics / Q000378:metabolism; D008164:Luminescent Proteins / Q000032:analysis; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D009475:Neurons, Afferent / Q000166:cytology / Q000378:metabolism*; D009479:Neuropeptides; D011679:Pupa / Q000166:cytology / Q000254:growth & development / Q000378:metabolism; D043562:Receptors, G-Protein-Coupled; D012679:Sense Organs / Q000166:cytology / Q000254:growth & development* / Q000378:metabolism; D008941:Spindle Apparatus / Q000235:genetics / Q000378:metabolism; D013234:Stem Cells / Q000166:cytology / Q000378:metabolism*
D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D003598:Cytoskeletal Proteins; D029721:Drosophila Proteins; D051157:Frizzled Receptors; D007202:Indicators and Reagents; D007605:Juvenile Hormones; D008164:Luminescent Proteins; D008565:Membrane Proteins; C107613:Mira protein, Drosophila; D009479:Neuropeptides; C115164:PON protein, Drosophila; D043562:Receptors, G-Protein-Coupled; C058784:fz protein, Drosophila; C098678:insc protein, Drosophila; C060606:numb protein, Drosophila; D049452:Green Fluorescent Proteins