PURPOSE We analyzed the expression of critical cell cycle regulators cyclin E and cyclin D1 in familial breast cancer, focusing on BRCA mutation-negative tumors. Cyclin E expression in tumors of BRCA1 or BRCA2 carriers is higher, and cyclin D1 expression lower, than in sporadic tumors. In familial non-BRCA1/2 tumors, cyclin E and cyclin D1 expression has not been studied. EXPERIMENTAL DESIGN ...

Ubiquitination of murine cyclin E is triggered by phosphorylation on threonine 393. Cyclin E(T393A) knockin mice exhibited increased cyclin E stability, but no phenotypic abnormalities. Importantly, loss of the p53 pathway exacerbated the effect of the T393A mutation. Thus, in p21(-/-) cells the T393A mutation had an exaggerated effect on cyclin E abundance and its associated kinase activity, w...

BACKGROUND Cyclin E, in conjunction with its catalytic partner cdk2, is rate limiting for entry into the S phase of the cell cycle. Cancer cells frequently contain mutations within the cyclin D-Retinoblastoma protein pathway that lead to inappropriate cyclin E-cdk2 activation. Although deregulated cyclin E-cdk2 activity is believed to directly contribute to the neoplastic progression of these c...

Putting Cyclin E in the trash L u and Pfeffer uncover a protein that helps remove Cyclin E after it has outlasted its usefulness. Cyclin E pushes cells from G1 into S phase. But if the protein lingers in cells, they can’t progress normally through the rest of the cell cycle. During S phase, the SCF pathway directs phosphorylated Cyclin E to the proteasome for destruction. A second, little-known...

Cyclin E, a G(1) cyclin, is overexpressed and present in low molecular weight (LMW) isoforms in breast cancer cells and tumor tissues. In this study we have examined the possibility that the shortened mRNA splice variants could give rise to tumor-specific cyclin E LMW proteins. We used the Splice Capture method to identify, enumerate and isolate known spliced mRNAs and to look for previously un...

Mitosis-promoting factor (MPF) is a complex formed by cyclin B (cyclin B) and cyclin-dependent kinase (cdc2). To investigate the role of MPF in reproduction Exopalaemon carinicauda, we cloned its full-length cDNA Ec-cyclin Ec-cdc2 genes. We analyzed their molecular characteristics expression profiles during ovarian embryonic development. The results showed that gene was 1194 bp long encoded 397...

Inactivation of Cyclin E-Cdk2 is essential for a timely arrest of the epidermal cell proliferation program during Drosophila embryogenesis. E-type cyclin-cdk complexes are thought to be activated by D-types titrating away inhibitors and inducing cyclin E transcription by activating E2F transcription factors via Rb phosphorylation. Therefore, we have analyzed whether the developmentally controll...

Progression through G1-S transition and S phase of the cell cycle is mediated by cyclin-dependent kinase 2 (cdk2), which interacts with several cyclins. Two of these, cyclin E and cyclin A2 (also known as cyclin A), are overexpressed in many cancers. Cyclin E2 and cyclin A1 are recently discovered cdk2-interacting cyclins that are found in malignant tumor cell lines and in acute myeloid leukemi...

Using Western blot analysis, we examined cyclin E and cyclin A protein levels in 19 patients with acute lymphoblastic leukemia ([ALL] 15 B-ALL and four T-ALL). Whereas normal, nonproliferating peripheral blood mononuclear cells (PBMCs) expressed low levels of the 50-kD cyclin E, ALL blasts in the peripheral blood, although showing low-level or no proliferation as judged by FACS/cell-cycle analy...

Cyclin E, a positive regulatory subunit of Cdk2, normally accumulates periodically at the G1/S transition, where it promotes entry into S phase and other DNA replication-associated functions. However, in many types of human cancer, cyclin E is overexpressed and in some cases its expression becomes deregulated, a phenomenon generally associated with poor prognosis. Although it is not yet known h...