High impact information on LOC397885

• Ablation of cyclin A messenger RNA in cytostatic factor/metaphase-arrested extracts of Xenopus eggs, followed by in vitro progression into interphase, resulted in the premature appearance of cyclin B-cdc2-associated H1 kinase activity and premature entry into mitosis [1].
• Role for cyclin A in the dependence of mitosis on completion of DNA replication [1].
• This suggests that cyclin A has a distinct role in cell-cycle progression [1].
• Although cyclin A-ablated extracts could initiate DNA synthesis during interphase, S phase was not completed before entry into mitosis [1].
• XDRP1 binds to both embryonic and somatic forms of cyclin A (A1 and A2) in Xenopus cells, but not to B-type cyclins [2].

Biological context of LOC397885

• The cyclin A polypeptide is associated with a protein that cross-reacts with an antibody against the conserved 'PSTAIR' epitope of p34cdc2, and the cyclin A-cdc2 complex exhibits protein kinase activity that oscillates with the cell cycle [3].
• XDRP1 is a nuclear phosphoprotein in Xenopus cells, and its phosphorylation is mediated by cyclin A-dependent kinase [2].
• A recent report demonstrates that the 3' untranslated region of the cyclin A1, B1, B2 and c-mos mRNAs determines the timing and extent of their cytoplasmic polyadenylation and translational activation during Xenopus oocyte maturation [4].
• However, embryos treated with the same dose of gamma-IR after the midblastula transition developed normally and exhibited no signs of apoptosis, no change in cyclin A1 level, and no increase in cyclin A1-Cdk2 activity [5].
• High doses of gamma-irradiation (gamma-IR) before the midblastula transition induced apoptotic cell death and increased the levels of cyclin A1 and cyclin A1-Cdk2 activity [5].

Anatomical context of LOC397885

• This kinase activity rises more smoothly than that of the cyclin B-cdc2 complexes and reaches a peak earlier in the cell cycle; indeed, cyclin A is destroyed before nuclear envelope breakdown [3].

References