Mother-daughter precursor cell fate transformation after Cdc2 down-regulation in the Drosophila bristle lineage.
The Drosophila bristle lineage is an excellent system in which to study how cell cycle and fate determination are synchronized in invariant cell lineages. In this model, five different cells arise from a single precursor cell, pI, after four asymmetric cell divisions. Cell diversity is achieved by the asymmetric segregation of cell determinants, such as Numb and Neuralized (Neur), resulting in differential activation of the Notch (N) pathway. We show that down-regulation of Cdc2, by over-expressing Tribbles, Dwee1, and Dmyt1 (three negative regulators of Cdc2) or by using thermo-sensitive Cdc2 mutant flies, delayed pI mitosis, and altered the polarity and the number of subsequent cell divisions. These modifications were associated with a mother-daughter cell fate transformation as the pI cell acquired the identity of the secondary precursor cell, pIIb. This type of change in cell identity only occurred when the N signaling pathway was inactive since ectopic N signaling transformed pI to pIIa-progeny fate. These transformations in cell identity suggest that, although synchronized, cell cycle and fate determination are independent phenomena in the bristle lineage.
Fichelson
Pierre
P
UMR 7622, CNRS-Université Paris VI, 9, Quai St. Bernard, 75252 Paris Cedex 05, France.
Gho
Michel
M
D000818:Animals; D016203:CDC2 Protein Kinase / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D002453:Cell Cycle / Q000502:physiology; D019070:Cell Lineage; D015536:Down-Regulation; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism; D004331:Drosophila melanogaster / Q000033:anatomy & histology / Q000166:cytology / Q000235:genetics / Q000502:physiology*; D009474:Neurons / Q000166:cytology / Q000502:physiology; D010641:Phenotype; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D013234:Stem Cells / Q000166:cytology / Q000502:physiology*; D019076:Transgenes
D029721:Drosophila Proteins; D011993:Recombinant Fusion Proteins; D016203:CDC2 Protein Kinase