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Antisense knockdown of cyclin E does not affect the midblastula transition in Xenopus laevis embryos.
- Source :
-
Cell cycle (Georgetown, Tex.) [Cell Cycle] 2005 Oct; Vol. 4 (10), pp. 1396-402. Date of Electronic Publication: 2005 Oct 18. - Publication Year :
- 2005
-
Abstract
- In Xenopus laevis embryos, cyclin E protein remains constitutively high throughout the first 12 cell cycles following fertilization until the onset of the midblastula transition (MBT) (after the 12(th) cell cycle) when it undergoes a dramatic reduction. The disappearance of cyclin E at the MBT occurs independently of active cell cycle progression, zygotic transcription, protein synthesis and the nuclear to cytoplasmic ratio. This has suggested that cyclin E is part of an autonomous maternal timer that regulates the onset of the MBT. To determine how constitutively high levels of cyclin E are maintained prior to the MBT and to investigate if the reduction in cyclin E protein affects the timing of the MBT, we have knocked down endogenous cyclin E mRNA using an N,N-diethyl-ethylene-diamine modified antisense oligonucleotide targeted to its open reading frame. We report that maintenance of high levels of cyclin E protein before the MBT is due to a balance between ongoing translation and proteolytic degradation. In support of our antisense experiments, polysome analysis demonstrates that cyclin E mRNA is associated with the translated fraction prior to the MBT. Furthermore, knockdown of cyclin E was not associated with defects in the timing of developmental events. Our data suggests that cyclin E is not required for the later cell cycles of embryonic development and that the pathway effecting downregulation of cyclin E rather then cyclin E degradation itself may be part of a maternal timer that affects the onset of the MBT.
- Subjects :
- Animals
Base Sequence
Cyclin A genetics
Cyclin A metabolism
Cyclin E metabolism
Embryo, Nonmammalian embryology
Embryo, Nonmammalian metabolism
Polyribosomes metabolism
Protein Biosynthesis genetics
RNA, Messenger genetics
Xenopus laevis genetics
Cyclin E deficiency
Cyclin E genetics
Oligodeoxyribonucleotides, Antisense genetics
Oligodeoxyribonucleotides, Antisense metabolism
Xenopus laevis embryology
Xenopus laevis metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 1551-4005
- Volume :
- 4
- Issue :
- 10
- Database :
- MEDLINE
- Journal :
- Cell cycle (Georgetown, Tex.)
- Publication Type :
- Academic Journal
- Accession number :
- 16131839
- Full Text :
- https://doi.org/10.4161/cc.4.10.2035