Distinct modes of cyclin E/Cdc2c kinase regulation and S-phase control in mitotic and endoreduplicating cycles of Drosophila embryogenesis
Date
1995
Authors
Sauer, Karsten
Knoblich, Jurgen A.
Richardson, Helena Elizabeth
Lehner, Christian F.
Editors
Advisors
Journal Title
Journal ISSN
Volume Title
Type:
Journal article
Citation
Genes and Development, 1995; 9(11):1327-1339
Statement of Responsibility
Karsten Sauer, Jürgen A. Knoblich, Helena Richardson, and Christian F. Lehner
Conference Name
Abstract
Drosophila cyclin E (DmcycE) is required in embryos for S phase of mitotic and endoreduplication cycles. Here, we describe regulatory differences characteristic for these two cell cycle types. While DmcycE transcript levels decline in DmcycE mutant cells programmed for mitotic proliferation, they are maintained and no longer restricted to transient pulses in DmcycE mutant cells programmed for endoreduplication. Moreover, DmcycE expression in endoreduplicating cells is down-regulated by ectopic expression of a heat-inducible cyclin E transgene. DmcycE expression in endoreduplicating tissues, therefore, is restricted by a negative feedback to the transient pulse triggering entry into S-phase. Conversely, during mitotic cycles, where S phase entry is not only dependent on cyclin E but also on progression through M phase, cyclin E and associated Dmcdc2c kinase activity are present throughout the cell cycle. Reinitiation of DNA replication during the G2 phase of the mitotic cell cycle, therefore, is prevented by cyclin E/Dmcdc2c kinase-independent regulation. Observations in cyclin A mutants implicate G2 cyclins in this regulation. Our results suggest molecular explanations for the different rules governing S phase during mitotic and endoreduplication cycles.
School/Discipline
Dissertation Note
Provenance
Description
Access Status
Rights
© 1995 by Cold Spring Harbor Laboratory Press