The roles of Drosophila cyclins A and B in mitotic control.
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.
Lehner
C F
CF
Department of Biochemistry and Biophysics, University of California, San Francisco 94143.
O'Farrell
P H
PH
D000595:Amino Acid Sequence; D000818:Animals; D000906:Antibodies; D001483:Base Sequence; D005075:Biological Evolution; D002453:Cell Cycle; D003001:Cloning, Molecular; D016213:Cyclins; D004330:Drosophila / Q000166:cytology / Q000196:embryology / Q000235:genetics*; D004625:Embryo, Nonmammalian / Q000166:cytology; D015870:Gene Expression; D005796:Genes; D007301:Insect Hormones / Q000235:genetics* / Q000302:isolation & purification / Q000502:physiology; D007399:Interphase; D007447:Invertebrate Hormones / Q000235:genetics* / Q000302:isolation & purification / Q000502:physiology; D008938:Mitosis; D008969:Molecular Sequence Data; D009154:Mutation; D009693:Nucleic Acid Hybridization; D012689:Sequence Homology, Nucleic Acid
D000906:Antibodies; D016213:Cyclins; D007301:Insect Hormones; D007447:Invertebrate Hormones