Mitotic cyclins are abruptly degraded at the end of mitosis by a cell-cycle-regulated ubiquitin-dependent proteolytic system. To understand how cyclin is recognized for ubiquitin conjugation, we have performed a mutagenic analysis of the destruction signal of mitotic cyclins. We demonstrate that an N-terminal cyclin B segment as short as 27 residues, containing the 9-amino-acid destruction box,...

Cyclins, TFIIB and RB play major roles in cell cycle and/or gene regulation. Earlier work has suggested common ancestry for the TFIIB repeats and RB pocket B which share 20% sequence identity. We now report that database searches with profiles based on a multiple alignment of cyclin core regions (the 'cyclin box') detect the TFIIB repeats with equivalent scores to divergent cyclins. Several fea...

Cyclins are primary regulators of the activity of cyclin-dependent kinases, which are known to play critical roles in controlling eukaryotic cell cycle progression. While there has been extensive research on cell cycle mechanisms and cyclin function in animals and yeasts, only a small number of plant cyclins have been characterized functionally. In this paper, we describe an exhaustive search f...

In hydra all cell-cycle control occurs in the G2/M transition. Cyclins acting at this restriction point in the cell cycle belong to the cyclin A and B families. In agreement with this we isolated cDNAs coding for a cyclin A and a cyclin B from the multiheaded mutant of Chlorohydra viridissima and a cyclin B from Hydra vulgaris. The two B-type cyclins from hydra show 85.6% identity at the amino ...

Oral mucosal cancer is a type of that develops from the lining oral cavity (mucosa). The main risk factors are smoking and drinking alcohol. pathogenesis involves various interrelated etiologies such as alcohol consumption, human papilloma virus (HPV), patients who have undergone hemopoietic stem cell transplants (stem transplants). Meanwhile, it does not rule out possibility internal genetics....

Although microglia exist as a minor glial cell type in the normal state of brain, they increase number response to various disorders and insults. However, it remains unclear whether proliferate affected area, mechanism proliferation has long attracted attention researchers. We analyzed microglial mitosis using facial nerve transection model which blood–brain barrier is left unimpaired when nerv...

At least four Cdk's –Cdk4, Cdk6, Cdk2 and Cdk1– are thought to play key roles during the different phases of the cell cycle (Figure 1). For instance, Cdk4 and Cdk6, two kinases that can only be activated by D-type cyclins, are thought to be essential in allowing cells to exit quiescence (G0) by initiating the sequential phosphorylation of the retinoblastoma protein (pRB). Partially phosphorylat...

Using the conditionally immortalized human cell line tsFHI, we have investigated the role of cyclin-dependent kinase inhibitors (CKIs) in intestinal epithelial cell differentiation. Expression of cyclins, cyclin-dependent kinases (Cdk), and CKIs was examined under conditions promoting growth, growth arrest, or expression of differentiated traits. Formation of complexes among cell cycle regulato...