High impact information on CCNB1

• Inhibition of poly(A) polymerase requires p34cdc2/cyclin B phosphorylation of multiple consensus and non-consensus sites [1].
• Degradation of cyclin B is triggered by increased levels of active cdc2 and is required for exit from mitosis [2].
• Experimental conditions were established under which a fusion protein containing an amino-terminal fragment of cyclin B is ligated to ubiquitin only in extracts from M-phase but not from interphase cells [2].
• Expression of cyclin B1 messenger RNA isoforms and initiation of cytoplasmic polyadenylation in the bovine oocyte [3].
• Our results also show a link between cytoplasmic polyadenylation of cyclin B1 and translation/appearance of cyclin B1 protein before in vitro maturation [3].

Biological context of CCNB1

• We have found that cyclin B1 mRNA is present in two isoforms, consisting of the same open reading frame but with different 3'-UTR lengths [3].
• Cyclin B, a positive regulatory subunit of the cdc2 protein kinase complex, is synthesized across the cell cycle and then rapidly degraded at the end of mitosis [2].
• Destruction of cyclin B is responsible for inactivation of MPF, while phosphorylation of cdc2 is likely responsible for maintaining its low activity [4].
• But when reverse transcription was performed with oligo(dT), amplification was dramatically reduced after maturation, except for cyclin B1 mRNA, implying deadenylation without degradation of three transcripts [5].
• RA does not modify expression of cyclin B1 and HI genes in the bovine oocyte, and probably does not generate oxidative stress [6].

Anatomical context of CCNB1

• The transcript corresponding to cyclin B1 in goat granulosa cells is 1.8 kb [7].
• The differential expression of three selected candidate genes that were identified as putatively upregulated in the early cleaving zygotes were chosen for further investigations; histone H3, cyclin B1, and GDF-9B [8].

Associations of CCNB1 with chemical compounds

• Further analysis of constituent cell cycle proteins of these kinases by Western blot showed that A23187 alone could not induce changes in cdc2, cdc25, or ERK2 but induced reduction of cyclin B1 [4].
• The overall objective was to evaluate the effectiveness of the S-enantiomer of roscovitine (inhibitor of p34cdc2/cyclin B kinase) to maintain bovine cumulus-oocyte complexes at the germinal vesicle (GV) stage for extended times after removal from antral follicles without compromising subsequent maturation, fertilization and embryo development [9].
• After emodin treatment, there was a down-regulation of Cyclin B1, P34cdc2, and Bcl-2 protein expression while the Bax protein expression was unaffected [10].

Other interactions of CCNB1

• Identification of cDNAs encoding bovine cyclin B and Cdk1/Cdc2 [11].
• An inconstant elongation of the poly(A) tail was observed for cyclin A2 transcripts after maturation, while a constant lengthening was observed for cyclin B1, occurring during the first 12 hr of incubation [12].
• Cumulus-free oocytes were analyzed for poly-(A) mRNA contents and relative mRNA expression of genes involved in cell cycle regulation (cyclin B1 and H1) and antioxidative defence (Mn-superoxide dismutase and glucose-6-phosphate dehydrogenase) [6].
• We identified several known genes like cyclin B1, splicing factor ccl.4, cytochrome c oxidase, and mineralocorticoid receptor while numerous other clones remain unidentified [13].
• The injection of cyclin B1 dsRNA resulted in a decrease in cyclin B1 mRNA and protein, while the cyclin B2 mRNA remained unaffected [14].

Analytical, diagnostic and therapeutic context of CCNB1

• Because oocytes collected from very small follicles have high levels of cyclin B1 mRNA, the onset of its accumulation in the oocytes was evaluated by in situ hybridization of fetal ovaries [15].
• The cyclin B1 clone was used as a probe to evaluate its follicular size specificity on virtual Northern blot [13].
• This probe was easily obtained by polymerase-chain-reaction (PCR) on reverse-transcribed mRNA from granulosa cells, using cyclin B specific primers derived from a bovine cDNA [7].

References