The anaphase promoting complex/cyclosome is required during development for modified cell cycles.
Animals and plants use modified cell cycles to achieve particular developmental strategies. In one common example, most animals and plants have tissues in which the cells become polyploid or polytene by means of an S-G cycle, but the mechanism by which mitosis is inhibited in the endo cycle is not understood. The Drosophila morula (mr) gene regulates variant cell cycles, because in addition to disrupting the archetypal cycle (G1-S-G2-M), mr mutations affect the rapid embryonic (S-M) divisions as well as the endo cycle (S-G) that produces polyploid cells. In dividing cells mr mutations cause a metaphase arrest, and endo cycling nurse cells inappropriately reenter mitosis in mr mutants. We show mr encodes the APC2 subunit of the anaphase promoting complex/cyclosome. This finding demonstrates that anaphase promoting complex/cyclosome is required not only in proliferating cells but also to block mitosis in some endo cycles. The mr mutants further indicate that transient mitotic functions in endo cycles change chromosome morphology from polytene to polyploid.
Kashevsky
Helena
H
Whitehead Institute, Massachusetts Institute of Technology, Cambridge, MA 02142, USA.
Wallace
Julie A
JA
Reed
Bruce H
BH
Lai
Cary
C
Hayashi-Hagihara
Aki
A
Orr-Weaver
Terry L
TL
D000595:Amino Acid Sequence; D064173:Anaphase-Promoting Complex-Cyclosome; D000818:Animals; D030801:Animals, Genetically Modified; D002453:Cell Cycle / Q000502:physiology*; D002455:Cell Division / Q000235:genetics / Q000502:physiology; D003001:Cloning, Molecular; D004330:Drosophila / Q000235:genetics* / Q000254:growth & development; D004625:Embryo, Nonmammalian / Q000502:physiology; D005260:Female; D018507:Gene Expression Regulation, Developmental; D008025:Ligases / Q000235:genetics* / Q000502:physiology; D008938:Mitosis / Q000502:physiology; D008969:Molecular Sequence Data; D016296:Mutagenesis; D016366:Open Reading Frames; D010053:Ovary / Q000502:physiology; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D043743:Ubiquitin-Protein Ligase Complexes
D043743:Ubiquitin-Protein Ligase Complexes; D064173:Anaphase-Promoting Complex-Cyclosome; D008025:Ligases