The mitotic-to-endocycle switch in Drosophila follicle cells is executed by Notch-dependent regulation of G1/S, G2/M and M/G1 cell-cycle transitions

The Notch signaling pathway controls the follicle cell mitotic-to-endocycle transition in Drosophila oogenesis by stopping the mitotic cycle and promoting the endocycle. To understand how the Notch pathway coordinates this process, we have identified and performed a functional analysis of genes whose transcription is responsive to the Notch pathway at this transition. These genes include the G2/M regulator Cdc25 phosphatase, String; a regulator of the APC ubiquitination complex Hec/CdhFzr and an inhibitor of the CyclinE/CDK complex, Dacapo. Notch activity leads to downregulation of String and Dacapo, and activation of Fzr. All three genes are independently responsive to Notch. In addition, CdhFzr, an essential gene for endocycles, is sufficient to stop mitotic cycle and promote precocious endocycles when expressed prematurely during mitotic stages. In contrast, overexpression of the growth controller Myc does not induce premature endocycles but accelerates the kinetics of normal endocycles. We also show that Archipelago (Ago), a SCF-regulator is dispensable for mitosis, but crucial for endocycle progression in follicle epithelium. The results support a model in which Notch activity executes the mitotic-to-endocycle switch by regulating all three major cell cycle transitions. Repression of String blocks the M-phase, activation of Fzr allows G1 progression and repression of Dacapo assures entry into the S-phase. This study provides a comprehensive picture of the logic that external signaling pathways may use to control cell cycle transitions by the coordinated regulation of the cell cycle.

[1]  Robert Walgate,et al.  Proliferation , 1985, Nature.

[2]  T. Möröy,et al.  Loss of p27Kip1 cooperates with cyclin E in T-cell lymphomagenesis , 2003, Oncogene.

[3]  P. O’Farrell,et al.  Fluctuations in Cyclin E levels are required for multiple rounds of endocycle S phase in Drosophila , 1998, Current Biology.

[4]  I. Hariharan,et al.  The coupling of cell growth to the cell cycle. , 2001, Current opinion in cell biology.

[5]  C. Lehner,et al.  Drosophila p27Dacapo expression during embryogenesis is controlled by a complex regulatory region independent of cell cycle progression. , 2002, Development.

[6]  H. Ruohola-Baker,et al.  Mosaic analysis in the drosophila ovary reveals a common hedgehog-inducible precursor stage for stalk and polar cells. , 1999, Genetics.

[7]  K. Ravid,et al.  Polyploidy: occurrence in nature, mechanisms, and significance for the megakaryocyte-platelet system. , 2000, Experimental hematology.

[8]  B. Calvi,et al.  Fluorescent BrdU labeling and nuclear flow sorting of the Drosophila ovary. , 2004, Methods in molecular biology.

[9]  J. Cross.  Genetic insights into trophoblast differentiation and placental morphogenesis. , 2000, Seminars in cell & developmental biology.

[10]  P. Simpson,et al.  The choice of cell fate in the epidermis of Drosophila , 1991, Cell.

[11]  H. Johnston,et al.  Delta signaling from the germ line controls the proliferation and differentiation of the somatic follicle cells during Drosophila oogenesis , 2001 .

[12]  Mark J. Murphy,et al.  c-Myc regulates mammalian body size by controlling cell number but not cell size , 2001, Nature.

[13]  C. Lehner,et al.  Distinct modes of cyclin E/cdc2c kinase regulation and S-phase control in mitotic and endoreduplication cycles of Drosophila embryogenesis. , 1995, Genes & development.

[14]  C. Lehner,et al.  Cyclin E controls S phase progression and its down-regulation during Drosophila embryogenesis is required for the arrest of cell proliferation , 1994, Cell.

[15]  W. Du,et al.  DNA replication control through interaction of E2F–RB and the origin recognition complex , 2001, Nature Cell Biology.

[16]  S. Reed,et al.  Activation of cyclin E/CDK2 is coupled to site‐specific autophosphorylation and ubiquitin‐dependent degradation of cyclin E. , 1996, The EMBO journal.

[17]  J. S. Britton,et al.  Cis-regulatory elements of the mitotic regulator, string/Cdc25. , 1999, Development.

[18]  A. Spradling,et al.  The Drosophila endocycle is controlled by Cyclin E and lacks a checkpoint ensuring S-phase completion. , 1996, Genes & development.

[19]  B. Barrell,et al.  Mapping and identification of essential gene functions on the X chromosome of Drosophila , 2002, EMBO reports.

[20]  A. Spradling,et al.  Cell cycle control of chorion gene amplification. , 1998, Genes & development.

[21]  S. Beckendorf,et al.  The COP9 signalosome promotes degradation of Cyclin E during early Drosophila oogenesis. , 2003, Developmental cell.

[22]  S. Reed,et al.  Human F-box protein hCdc4 targets cyclin E for proteolysis and is mutated in a breast cancer cell line , 2001, Nature.

[23]  Jan-Michael Peters,et al.  The anaphase-promoting complex: proteolysis in mitosis and beyond. , 2002, Molecular cell.

[24]  J. Peters,et al.  A Conserved Cyclin-Binding Domain Determines Functional Interplay between Anaphase-Promoting Complex–Cdh1 and Cyclin A-Cdk2 during Cell Cycle Progression , 2001, Molecular and Cellular Biology.

[25]  I. Hariharan,et al.  Expression of the cyclin-dependent kinase inhibitor Dacapo is regulated by Cyclin E , 2000, Mechanisms of Development.

[26]  S. Braun,et al.  p21cip-1/waf-1 Deficiency Causes Deformed Nuclear Architecture, Centriole Overduplication, Polyploidy, and Relaxed Microtubule Damage Checkpoints in Human Hematopoietic Cells , 1999 .

[27]  S. Hou,et al.  Cyclin D-Cdk4 and cyclin E-Cdk2 regulate the Jak/STAT signal transduction pathway in Drosophila. , 2003, Developmental cell.

[28]  D. St Johnston,et al.  Delta signaling from the germ line controls the proliferation and differentiation of the somatic follicle cells during Drosophila oogenesis. , 2001, Genes & development.

[29]  H. Vodermaier,et al.  Cell cycle: Waiters serving the Destruction machinery , 2001, Current Biology.

[30]  Freddy Radtke,et al.  Notch signaling is a direct determinant of keratinocyte growth arrest and entry into differentiation , 2001, The EMBO journal.

[31]  N. Pavletich.  Mechanisms of cyclin-dependent kinase regulation: structures of Cdks, their cyclin activators, and Cip and INK4 inhibitors. , 1999, Journal of molecular biology.

[32]  Y. Jan,et al.  Delta and Serrate are redundant Notch ligands required for asymmetric cell divisions within the Drosophila sensory organ lineage. , 1998, Genes & development.

[33]  R. K. Herman.  Mosaic analysis. , 1995, Methods in Cell Biology.

[34]  W. Pledger,et al.  Paradigms of Growth Control: Relation to Cdk Activation , 2002, Science's STKE.

[35]  C. Lehner,et al.  Drosophila fizzy-related Down-Regulates Mitotic Cyclins and Is Required for Cell Proliferation Arrest and Entry into Endocycles , 1997, Cell.

[36]  S. Zipursky,et al.  Induction of Drosophila eye development by decapentaplegic. , 1997, Development.

[37]  Hans Clevers,et al.  Notch1 functions as a tumor suppressor in mouse skin , 2003, Nature Genetics.

[38]  S. Shousha,et al.  High level expression of p27(kip1) and cyclin D1 in some human breast cancer cells: inverse correlation between the expression of p27(kip1) and degree of malignancy in human breast and colorectal cancers. , 1997, Proceedings of the National Academy of Sciences of the United States of America.

[39]  C. Lehner,et al.  Exit from mitosis is regulated by Drosophila fizzy and the sequential destruction of cyclins A, B and B3. , 1995, The EMBO journal.

[40]  S. Elledge,et al.  Phosphorylation-Dependent Ubiquitination of Cyclin E by the SCFFbw7 Ubiquitin Ligase , 2001, Science.

[41]  Hannele Ruohola-Baker,et al.  Notch-Dependent Fizzy-Related/Hec1/Cdh1 Expression Is Required for the Mitotic-to-Endocycle Transition in Drosophila Follicle Cells , 2004, Current Biology.

[42]  D. Prober,et al.  Drosophila myc Regulates Cellular Growth during Development , 1999, Cell.

[43]  S. Braun,et al.  p21(cip-1/waf-1) deficiency causes deformed nuclear architecture, centriole overduplication, polyploidy, and relaxed microtubule damage checkpoints in human hematopoietic cells. , 1999, Blood.

[44]  B. Edgar,et al.  The Drosophila Cyclin D–Cdk4 complex promotes cellular growth , 2000, The EMBO journal.

[45]  H. Ruohola-Baker,et al.  Role of Notch pathway in terminal follicle cell differentiation during Drosophila oogenesis , 1999, Development Genes and Evolution.

[46]  C. Lehner,et al.  Continuous Cyclin E expression inhibits progression through endoreduplication cycles in Drosophila , 1998, Current Biology.

[47]  D. Levens,et al.  Reconstructing MYC. , 2003, Genes & development.

[48]  H. Ruohola-Baker,et al.  Notch-Delta signaling induces a transition from mitotic cell cycle to endocycle in Drosophila follicle cells. , 2001, Development.

[49]  A. Spradling,et al.  Chorion gene amplification in Drosophila: A model for metazoan origins of DNA replication and S-phase control. , 1999, Methods.

[50]  C. Lehner,et al.  Completion of Mitosis Requires Neither fzr/rap nor fzr2, a Male Germline-Specific Drosophila Cdh1 Homolog , 2002, Current Biology.

[51]  B. Edgar,et al.  Drosophila Cdk4 is required for normal growth and is dispensable for cell cycle progression , 2000, The EMBO journal.

[52]  David Stein,et al.  Drosophila dMyc is required for ovary cell growth and endoreplication , 2004, Development.

[53]  T. Orr-Weaver.  Drosophila chorion genes: Cracking the eggshell's secrets , 1991, BioEssays : news and reviews in molecular, cellular and developmental biology.

[54]  B. Futcher.  Transcriptional regulatory networks and the yeast cell cycle. , 2002, Current opinion in cell biology.

[55]  M. Bownes,et al.  The function of the broad-complex during Drosophila melanogaster oogenesis. , 1999, Genetics.

[56]  Gavin Brooks,et al.  Cell Cycle Control , 2004, Methods in Molecular Biology™.

[57]  M. Graner,et al.  Requirements for the cytoplasmic domain of the alphaPS1, alphaPS2 and betaPS integrin subunits during Drosophila development. , 1998, Development.

[58]  A. Spradling.  ORC binding, gene amplification, and the nature of metazoan replication origins. , 1999, Genes & development.

[59]  J. Cross,et al.  Developmental restriction of Mash-2 expression in trophoblast correlates with potential activation of the notch-2 pathway. , 1997, Developmental genetics.

[60]  M. Lilly,et al.  The p27cip/kip ortholog dacapo maintains the Drosophila oocyte in prophase of meiosis I , 2003, Development.

[61]  Xinsheng Gao,et al.  TSC1 and TSC2 tumor suppressors antagonize insulin signaling in cell growth. , 2001, Genes & development.

[62]  Bert Vogelstein,et al.  Uncoupling of S phase and mitosis induced by anticancer agents in cells lacking p21 , 1996, Nature.

[63]  Yuh Nung Jan,et al.  Dacapo, a Cyclin-Dependent Kinase Inhibitor, Stops Cell Proliferation during Drosophila Development , 1996, Cell.

[64]  Daniel A. Haber,et al.  Archipelago regulates Cyclin E levels in Drosophila and is mutated in human cancer cell lines , 2001, Nature.

[65]  L. Johnston,et al.  Control of growth and organ size in Drosophila , 2002, BioEssays : news and reviews in molecular, cellular and developmental biology.

[66]  B. Edgar,et al.  Drosophila cyclin D/Cdk4 requires Hif-1 prolyl hydroxylase to drive cell growth. , 2004, Developmental cell.

[67]  R. Eisenman,et al.  c-Myc enhances protein synthesis and cell size during B lymphocyte development. , 1999, Proceedings of the National Academy of Sciences of the United States of America.