Cycimns were originally defined as proteins which are synthesized in each cell cycle and destroyed at every mitosis. Cyclins were discovered by T. Hunt and students at the Marine Biological Laboratory, Woods Hole, MA, duningthe 1982 Physiology Course (1). They labeled eggs ofthe sea urchin Arbacia punctulata with [35S]methionine after fertilization and analyzed the temporal pattern of protein s...

A critical DNA damage checkpoint in Saccharomyces cerevisiae is an arrest at the metaphase stage of mitosis. Here we show that the S-phase cyclins Clb5 and Clb6 are required for this arrest. Strains lacking Clb5 and Clb6 are hypersensitive to DNA damage. Furthermore, in the presence of the DNA alkylating agent methyl methanesulfonate (MMS) over 50% of clb5 clb6 mutants by-passed the metaphase c...

Cell division in eukaryotes is mediated by the action of the mitosis promoting factor, which is composed of the CDC2 protein kinase and one of the various mitotic cyclins. We have recently isolated a cdc2 gene from alfalfa. Here, we report the isolation of two cyclin genes, cycMs1 and cycMs2, from alfalfa. The cycMs2 gene shows highest similarity to type B cyclins. In contrast, the predicted am...

The timing mechanism for mitotic progression is still poorly understood. The spindle assembly checkpoint (SAC), whose reversal upon chromosome alignment is thought to time anaphase [1-3], is functional during the rapid mitotic cycles of the Drosophila embryo; but its genetic inactivation had no consequence on the timing of the early mitoses. Mitotic cyclins-Cyclin A, Cyclin B, and Cyclin B3-inf...

D-type cyclins (CycD) play key roles in linking the Arabidopsis cell cycle to extracellular and developmental signals, but little is known of their regulation at the post-transcriptional level or of their cyclin-dependent kinase (CDK) partners. Using new antisera to CycD2 and CycD3, we demonstrate that the CDK partner of these Arabidopsis cyclins is the PSTAIRE-containing CDK Cdc2a. Previous an...

Non-small-cell lung cancer (NSCLC) is among the most frequently diagnosed malignancy and a leading cause for cancer mortality worldwide. Despite various efforts, practical prognostic and predictive markers are still few. We review recent findings concerning the cell cycle in NSCLC and discuss prognostic and predictive aspects as well as the challenge of targeted therapeutic approaches. Deregula...

The γ-chain (γc) is a transducing element shared between several cytokine receptors whose alteration causes X-linked severe combined immunodeficiency. Recently, a direct involvement of γc in self-sufficient growth in a concentration-dependent manner was described, implying a direct relationship between the amount of the molecule and its role in cell cycle progression. In this study, we evaluate...

The retinoblastoma (Rb) family consists of the tumor suppressor pRb and related proteins pl07 and pRb2/pl30. Ectopie expression of pRb and p 1117results in a growth arrest of sensitive cells in the G, phase of the cell cycle. We demonstrated here that the growth-suppressive properties of pRb2/pl30 were also specific for the G, phase. The A-, E-, and D-type cyclins as well as transcription facto...

The retinoblastoma (Rb) family consists of the tumor suppressor pRb and related proteins p107 and pRb2/p130. Ectopic expression of pRb and p107 results in a growth arrest of sensitive cells in the G1 phase of the cell cycle. We demonstrated here that the growth-suppressive properties of pRb2/p130 were also specific for the G1 phase. The A-, E-, and D-type cyclins as well as transcription factor...