title: A critical role for cyclin E in cell fate determination in the central nervous system of Drosophila melanogaster.
abstract: We have examined the process by which cell diversity is generated in neuroblast (NB) lineages in the central nervous system of Drosophila melanogaster. Thoracic NB6-4 (NB6-4t) generates both neurons and glial cells, whereas NB6-4a generates only glial cells in abdominal segments. This is attributed to an asymmetric first division of NB6-4t, localizing prospero (pros) and glial cell missing (gcm) only to the glial precursor cell, and a symmetric division of NB6-4a, where both daughter cells express pros and gcm. Here we show that the NB6-4t lineage represents the ground state, which does not require the input of any homeotic gene, whereas the NB6-4a lineage is specified by the homeotic genes abd-A and Abd-B. They specify the NB6-4a lineage by down-regulating levels of the G1 cyclin, DmCycE (CycE). CycE, which is asymmetrically expressed after the first division of NB6-4t, functions upstream of pros and gcm to specify the neuronal sublineage. Loss of CycE function causes homeotic transformation of NB6-4t to NB6-4a, whereas ectopic CycE induces reverse transformations. However, other components of the cell cycle seem to have a minor role in this process, suggesting a critical role for CycE in regulating cell fate in segment-specific neural lineages.
authors.affiliation: Institute for Genetics, University of Mainz, D-55099 Mainz, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Berger
authors.forename: S K
authors.initials: SK
authors.lastname: Pallavi
authors.forename: Mohit
authors.initials: M
authors.lastname: Prasad
authors.forename: L S
authors.initials: LS
authors.lastname: Shashidhara
authors.forename: Gerhard M
authors.initials: GM
authors.lastname: Technau
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000235:genetics*; D019070:Cell Lineage / Q000235:genetics*; D002490:Central Nervous System / Q000166:cytology / Q000196:embryology* / Q000378:metabolism; D019927:Cyclin E / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins; D015536:Down-Regulation / Q000502:physiology; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism; D004331:Drosophila melanogaster / Q000196:embryology* / Q000235:genetics / Q000378:metabolism; D017952:Ganglia, Invertebrate / Q000166:cytology / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental / Q000502:physiology; D005801:Genes, Homeobox / Q000502:physiology; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D009457:Neuroglia / Q000166:cytology / Q000378:metabolism; D009474:Neurons / Q000166:cytology / Q000378:metabolism; D009479:Neuropeptides / Q000235:genetics / Q000378:metabolism; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D013234:Stem Cells / Q000166:cytology / Q000378:metabolism*; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: C062393:Abd-B proteins, Drosophila; D019927:Cyclin E; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; C102805:GCM protein, Drosophila; D018398:Homeodomain Proteins; D009419:Nerve Tissue Proteins; D009479:Neuropeptides; D009687:Nuclear Proteins; D015534:Trans-Activators; D014157:Transcription Factors; C073099:pros protein, Drosophila; C066591:abd-A protein, Drosophila