The Cell Cycle and Regulation of Cell Mass and Macronuclear DNA Content

Berger, James D.

doi:10.1007/978-3-642-73086-3_7

Cited by 22 publications

(10 citation statements)

References 66 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Li+ did not cause morphological changes in stationary phase cells. Li + prevented entry into division if applied before the division commitment point as defined by Berger [1988]. The analysis of the Li + effect on morphogenesis was therefore carried out on cells committed to division.…”

Section: Teratogenic Effects Of Lithiummentioning

confidence: 99%

“…Injections of a few pl of myo-inositol (0.25 M) were then carried out as well as injections of epiinositol, a biologically inactive isomer. Cells were injected at 0.7-0.95 of their division cycle, i.e., slightly before or after their division commitment point as defined by Berger [1988] and, under our culture conditions, between 90 and 20 min before entry into division. The injected cells were then observed and transferred into Li + -containing medium as soon as division started as in condition 1 (Fig.…”

Section: Myo-inositol Rescue Of Li+ Effectsmentioning

confidence: 99%

See 1 more Smart Citation

Lithium‐Induced respecification of pattern in Paramecium

Beisson

Ruiz

1992

Dev. Genet.

View full text Add to dashboard Cite

The long-known teratogenic effects (dorsalisation) of lithium on amphibian embryos has recently raised renewed interest. As it is known that lithium blocks the polyphosphoinositide (PI) cycle, causing a depressed level of myo-inositol, and as injections of myo-inositol have been shown to rescue the effects of Li +, it was postulated that Li + causes a flattening of gradients of PI cycle activity underlying the developmental polarities. We have studied the effect of Li' on the morphogenesis of the unicellular organism, Paramecium.We show 1) that exposure to 25 m M Li' during division yields precise distorsions of the cortical pattern that can be explained by a uniformisation of surface growth i.e. partial suppression of the right/left and antero/posterior asymmetries and 2) that Li' effects are rescued by injection of myoinositol. These results suggest that spatially graded activity of the PI cycle (ensuring in turn a spatially graded distribution of secondary messengers directly involved in the morphogenetic processes) appeared early in evolution. o 1992 Wiiey-Liss, Inc.

show abstract

Section: Teratogenic Effects Of Lithiummentioning

confidence: 99%

Section: Myo-inositol Rescue Of Li+ Effectsmentioning

confidence: 99%

Lithium‐Induced respecification of pattern in Paramecium

Beisson

Ruiz

1992

Dev. Genet.

View full text Add to dashboard Cite

show abstract

“…NG Berger, 1986;Rasmussen, Berger & Ching, 1986;Berger & Ching, 1988;Berger, 1988). It is customary to think that cell-pairing in conjugation constitutes a sharp demarcation between asexual and sexual development, in that once cell-pairing has taken place the conjugants terminate all asexual events and switch over to the sexual phase of development.…”

Section: Mechanistic Considerations Of Heterochronymentioning

confidence: 99%

Developmental Heterochrony in Ciliated Protozoa: Overlap of Asexual and Sexual Cycles During Conjugation

1990

Biological Reviews

View full text Add to dashboard Cite

“…The point of commitment to division (PCD) is located 90 min prior to fission during the preceding cell cycle. At this point, cells become irreversibly committed to division in the present cell cycle, the nature of the next cell cycle (meiotic or vegetative) is programmed, and the timing of Initiation of Macronuclear DNA Synthesis (IDS) is set if the following cell cycle is to be a vegetative cell cycle (Berger 1988).…”

mentioning

confidence: 99%

Two Distinct Classes of Mitotic Cyclin Homologues, Cyc1 and Cyc2, Are Involved In Cell Cycle Regulation In the Ciliate Paramecium Tetraurelia

Zhang

Adl

Berger

1999

J Eukaryotic Microbiology

Self Cite

View full text Add to dashboard Cite

The eukaryotic cell cycle is regulated by the sequential activation of different CDK/cyclin complexes. Two distinct classes of mitotic cyclin homologues, CYC1 and CYC2, have been identified and cloned for the first time in the ciliate Paramecium. Cyc1 is 324 amino acids long with a predicted molecular mass of 38 kDa, whereas Cyc2 is 336 amino acids long with a predicted molecular mass of 40 kDa. They display 42-51% sequence identity to other eukaryotic mitotic cyclins within the 'cyclin box' region. The conserved 'cyclin box' and 'destruction box' elements can be identified within each of the sequences. Genomic Southern blot analysis indicated that the CYC1 gene has two isoforms, with 92.3% and 85.9% identify at the amino acid level and at the nucleotide level, respectively. Both Cyc1 and Cyc2 proteins showed characteristic patterns of accumulation and destruction during the vegetative cell cycle, with Cyc1 peaking at the point of commitment to division (PCD), and Cyc2 reaching the maximal level late in the cell cycle. Immunoprecipitation experiments with antibodies specific to Cyc1 and Cyc2 indicated that Cyc1 and Cyc2 associate with distinct CDK homologues. Both immunoprecipitates exhibited histone H1 kinase activity that oscillated in the cell cycle in parallel with the respective amount of cyclins present. Histone H1 kinase activity associated with Cyc1 reached a peak at PCD while Cyc2 showed maximal activity when about 75% cells have completed cytokinesis. We propose that Cyc1 may be involved in commitment to division, in association with the CDK that binds to p13suc1, Cdk3, and that the Cyc2/Cdk2 complex may regulate cytokinesis. PCR-amplification revealed similar sequences in Tetrahymena, Sterkiella, Colpoda and Blepharisma, suggesting the conservation of the cyclin genes within ciliates. Although cell cycle regulation in ciliates differs in some respects from that of other eukaryotes, the cyclin motifs have clearly been conserved during evolution.

show abstract

The Cell Cycle and Regulation of Cell Mass and Macronuclear DNA Content

Cited by 22 publications

References 66 publications

Lithium‐Induced respecification of pattern in Paramecium

Lithium‐Induced respecification of pattern in Paramecium

Developmental Heterochrony in Ciliated Protozoa: Overlap of Asexual and Sexual Cycles During Conjugation

Two Distinct Classes of Mitotic Cyclin Homologues, Cyc1 and Cyc2, Are Involved In Cell Cycle Regulation In the Ciliate Paramecium Tetraurelia

Contact Info

Product

Resources

About