Cell fate specification by even-skipped expression in the Drosophila nervous system is coupled to cell cycle progression.
The correct specification of defined neurons in the Drosophila central nervous system is dependent on even-skipped. During CNS development, even-skipped expression starts in the ganglion mother cell resulting from the first asymmetric division of neuroblast NB 1-1. This first division of NB 1-1 (and of the other early neuroblasts as well) is temporally controlled by the transcriptional regulation of string expression, which we have manipulated experimentally, even-skipped expression still occurs if the first neuroblast division is delayed, but not if the division is prohibited. Moreover, even-skipped expression is also dependent on progression through S phase which follows immediately after the first division. However, cytokinesis during the first NB division is not required for even-skipped expression as revealed by observations in pebble mutant embryos. Our results demonstrate therefore that even-skipped expression is coupled to cell cycle progression, presumably in order to prevent a premature activation of expression by a positive regulator which is produced already in the neuroblast during G2 and segregated asymmetrically into the ganglion mother cell during mitosis.
Weigmann
K
K
Friedrich-Miescher-Laboratorium, Max-Planck-Gesellschaft, Tübingen, FRG.
Lehner
C F
CF
D000818:Animals; D001426:Bacterial Proteins; D002453:Cell Cycle / Q000235:genetics; D004330:Drosophila / Q000196:embryology* / Q000235:genetics*; D029721:Drosophila Proteins; D018507:Gene Expression Regulation, Developmental; D018398:Homeodomain Proteins / Q000235:genetics*; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D008845:Microinjections; D009420:Nervous System / Q000166:cytology / Q000196:embryology*; D009474:Neurons / Q000166:cytology / Q000502:physiology; D016196:S Phase; D013234:Stem Cells / Q000166:cytology / Q000502:physiology; D014157:Transcription Factors
D001426:Bacterial Proteins; D029721:Drosophila Proteins; D018398:Homeodomain Proteins; D014157:Transcription Factors; C052837:eve protein, Drosophila