1 Genes
| WormBase Gene ID | Gene Name | Sequence Name | Organism |
|---|---|---|---|
| WBGene00000865 | cyb-1 | ZC168.4 | Caenorhabditis elegans |
| Primary Identifier | Expr3273 | Remark | No GO_term assigned. |
| Subcellular Localization | In 6/6 fertilized embryos, GFP-CYB-1 levels began to decrease dramatically soon after spermatheca exit. The fluorescence intensity did not always begin to decrease immediately, but in 2/6 embryos remained stable for several minutes, indicating that exit from the spermatheca is not the direct trigger for cyclin B degradation. GFP-CYB-1 fluorescence in fertilized embryos decreased for approximately 12 min and then remained fairly stable for approximately 10 min. These two periods of rapid GFP-CYB-1 turnover and of GFP-CYB-1 stability coincide with the timing of meiosis I and meiosis II, respectively. Twenty to twenty-four minutes after the start of GFP-CYB-1 proteolysis, at a time when meiosis II is expected to be completed, fluorescence levels decreased again and approached zero. Pronuclei were observed at the end of this period indicating that the embryos had entered interphase. In 9/9 unfertilized embryos, GFP-CYB-1 fluorescence decreased rapidly after exit from the spermatheca just as in fertilized embryos. This is consistent with the occurrence of anaphase I in unfertilized embryos, in contrast with unfertilized vertebrate eggs which arrest at metaphase with high levels of cyclin B. A significant difference was observed between the unfertilized and the fertilized embryos at the time that meiosis II was expected to be completed in fertilized embryos. The second phase of decreasing GFP-CYB-1 fluorescence intensity did not occur in unfertilized embryos to the extent observed in fertilized embryos. At 27 min after spermatheca exit, GFP-CYB-1 fluorescence intensity was 7 +/- 5% (n = 6) of the value in the proximal oocyte in fertilized embryos and 19 +/- 10% (n = 9) in unfertilized embryos. This difference was statistically significant (P = .001) indicating that cyclin B proteolysis is not complete in unfertilized embryos. Pronuclei were observed at the end of these time-lapse sequences, indicating that unfertilized embryos entered interphase with a residual, metaphase II level of cyclin B. |
| WormBase Gene ID | Gene Name | Sequence Name | Organism |
|---|---|---|---|
| WBGene00000865 | cyb-1 | ZC168.4 | Caenorhabditis elegans |
