The cell cycle is a highly regulated process driven by endogenous factors that have regulatory functions. Certain proteins such as cyclins and cyclin-dependent kinases (cdks) are needed to progress through the four phases of the cell cycle. Cell cycle regulatory proteins have been characterized in somatic cells and exhibit phase specific expression patterns. However, the changes in expression of these proteins have not been characterized in early cleavage stage mouse embryos. This study utilized indirect immunofluorescence microscopy to determine the expression pattern of cell cycle regulators cyclin B 1, cyclin E, and CDK2 during the first three cell cycles of preimplantation mouse embryo development. Results suggest unique and specific patterns of expression for all three cell cycle regulators at different stages of the cell cycle. In G1 of the first cell cycle, cyclin E is expressed at high levels, whereas cyclin B 1 and CDK2 are expressed at moderate levels. During DNA synthesis (S phase), CDK2 levels slightly increase. However, cyclin B 1 and cyclin E levels begin to decline in S and continue to decrease to minimal levels in G2. CDK2 expression follows a similar trend during G2, decreasing considerably. During the second cell cycle, cyclin B 1 and CDK2 show staining patterns similar to the first cell cycle. The expression of cyclin E is maintained at a moderate level throughout the entire second cell cycle. Cyclin B 1, cyclin E, and CDK2 are all expressed at moderate levels during GI of the third cell cycle. During S phase, cyclin B 1 and CDK2 are maintained at moderate levels, but cyclin E is decreased to minimal levels. The expression of all three proteins was minimal during G2. This study provides baseline information on the unique expression patterns of cell cycle regulators in early mouse embryos. The determination of cell cycle protein expression will allow for a better understanding of the complex mechanisms in the division process during preimplantation mouse embryo development. / Department of Biology
| Identifer | oai:union.ndltd.org:BSU/oai:cardinalscholar.bsu.edu:handle/186406 |
| Date | January 1999 |
| Creators | Waclaw, Ronald Raymond |
| Contributors | Chatot, Clare L. |
| Source Sets | Ball State University |
| Detected Language | English |
| Format | vii, 67 leaves : ill. (some col.) ; 28 cm. |
| Source | Virtual Press |
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