Abstract
We have cloned, sequenced, and characterized the expression of a Drosophila cyclin B gene. The independent evolutionary conservation of A- and B-type cyclins implies that they have distinct roles. Indeed, in mutant embryos deficient in cyclin A, cells that accumulate only cyclin B do not enter mitosis. Thus, in vivo, cyclin B is not sufficient for mitosis. Furthermore, we find that the two cyclins are coexpressed in all proliferating cells throughout development. Though lacking a formal demonstration that cyclin B is essential as it is in other organisms, we propose that each of these proteins fulfills a distinct and essential role in the cell cycle.
Publication types
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Comparative Study
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, Non-P.H.S.
MeSH terms
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Amino Acid Sequence
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Animals
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Antibodies
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Base Sequence
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Biological Evolution
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Cell Cycle
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Cloning, Molecular
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Cyclins
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Drosophila / cytology
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Drosophila / embryology
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Drosophila / genetics*
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Embryo, Nonmammalian / cytology
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Gene Expression
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Genes
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Insect Hormones / genetics*
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Insect Hormones / isolation & purification
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Insect Hormones / physiology
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Interphase
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Invertebrate Hormones / genetics*
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Invertebrate Hormones / isolation & purification
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Invertebrate Hormones / physiology
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Mitosis*
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Molecular Sequence Data
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Mutation
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Nucleic Acid Hybridization
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Sequence Homology, Nucleic Acid
Substances
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Antibodies
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Cyclins
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Insect Hormones
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Invertebrate Hormones