Disease relevance of CYC1

• Altered cell cycle distribution, hyperplasia, and inhibited differentiation in Arabidopsis caused by the D-type cyclin CYCD3 [1].
• For this purpose, the expression, upon nematode infection, of two cell cycle markers was followed: a marker for division competence, the cyclin-dependent kinase cdc2a and a marker for the G2 phase, the mitotic cyclin cyc1At [2].

High impact information on CYC1

• To address this question, we examined the expression of cdc2 and cye genes, which encode the catalytic and regulatory subunits, respectively, of cyclin-dependent protein kinases that control progression through the cell cycle [3].
• Control of root growth and development by cyclin expression [3].
• Cytokinin activation of Arabidopsis cell division through a D-type cyclin [4].
• The D-type cyclin CycD3 was found to be elevated in a mutant of Arabidopsis with a high level of cytokinin and to be rapidly induced by cytokinin application in both cell cultures and whole plants [4].
• These results argue strongly that homolog interactions during meiotic prophase I require a novel meiosis-specific cyclin in Arabidopsis [5].

Biological context of CYC1

• Genes regulating the plant cell cycle: isolation of a mitotic-like cyclin from Arabidopsis thaliana [6].
• Analysis of putative cyclin-dependent kinase phosphorylation sites within CYCD3;1 shows that mutating Ser-343 to Ala enhances CYCD3;1 potency without affecting its rate of turnover and results in a fivefold increase in the level of cell death in response to sucrose removal [7].
• The A-type cyclin CYCA2;3 is a key regulator of ploidy levels in Arabidopsis endoreduplication [8].
• The D-type alfalfa cyclin gene cycMs4 complements G1 cyclin-deficient yeast and is induced in the G1 phase of the cell cycle [9].
• Novel functions of plant cyclin-dependent kinase inhibitors, ICK1/KRP1, can act non-cell-autonomously and inhibit entry into mitosis [10].

Anatomical context of CYC1

• Cyclin-dependent kinases and cyclins regulate with the help of different interacting proteins the progression through the eukaryotic cell cycle [11].
• Modulation of cyclin transcript levels in cultured cells of Arabidopsis thaliana [12].

Associations of CYC1 with chemical compounds

• Furthermore, results of whole-mount in situ hybridizations on roots treated with either oryzalin or hydroxyurea suggest that the different cyclin classes have distinct functions in the cell cycle [13].
• For the full activation of cyclin-dependent kinases (CDKs), not only cyclin binding but also phosphorylation of a threonine (Thr) residue within the T-loop is required [14].
• We have used liquid callus cultures and a cycloheximide-synchronized suspension culture of Arabidopsis to investigate changes in cyclin transcript levels in response to exogenous auxin, cytokinin, and nutrients, and during the cell cycle [12].
• ICK1, a cyclin-dependent protein kinase inhibitor from Arabidopsis thaliana interacts with both Cdc2a and CycD3, and its expression is induced by abscisic acid [15].
• An Arabidopsis line containing a fusion construct between the CYCB1;1 promoter and a bacterial beta-glucuronidase marker gene (uidA) was used in ethyl methanesulfonate mutagenesis [16].

Physical interactions of CYC1

• Identification of novel cyclin-dependent kinases interacting with the CKS1 protein of Arabidopsis [17].
• Phosphorylation by a cyclin-dependent kinase modulates DNA binding of the Arabidopsis heat-shock transcription factor HSF1 in vitro [18].

Other interactions of CYC1

• In Arabidopsis, we isolated cDNA encoding the D-type cyclin CYCD4;1 by a yeast (Saccharomyces cerevisiae) two-hybrid screening using CDKB2;1 as bait [19].
• Here, the isolation is reported of a new D-type cyclin gene (CYCD4;1) of Arabidopsis thaliana (L.) Heynh. during a two-hybrid screen using the cyclin-dependent kinase CDC2aAt as bait [20].
• However, induction of the cell cycle in the mutant background by overexpression of the D-type cyclin (CYCD3;1) was able to trigger complete rounds of cell division in the pericycle that did not result in lateral root formation [21].
• We find that ectopic expression of CYCLIN B1;2, not CYCLIN B1;1, induces mitotic divisions resulting in multicellular trichomes [22].
• The BARNASE gene was expressed in the Arabidopsis embryo under the control of two promoters, one from the cyclin AtCYCB1 gene and one from the AtLTP1 gene (Lipid Transfer Protein 1) [23].

Analytical, diagnostic and therapeutic context of CYC1

• Taking advantage of the situation that plants encode highly redundant cyclin A genes, we were able to perform functional dissection of CYCA2;3 using null mutant alleles [8].
• Whole-mount in situ hybridizations on roots showed that the cyclin mRNAs were confined to parts of the roots with mitotic activity [13].
• Microarray and reverse transcriptase-polymerase chain reaction analyses further provide expression profiles of cyclin genes in different tissues of wild-type Arabidopsis plants [24].
• Using a cDNA array, we identified genes that respond to BR in the det2 suspension culture of Arabidopsis, and found that epi-brassinolide upregulated transcription of the CycD3, a D-type plant cyclin gene through which cytokinin activates cell division [25].
• Here we report isolation of a new cyclin cDNA (cyclbAt) from Arabibopsis cDNA libraries using polymerase chain reaction amplified cyclin-box sequences as probes [26].

References