scholarly journals The Usefulness of Calyculin A for Cytogenetic Prenatal Diagnosis

2005 ◽  
Vol 53 (3) ◽  
pp. 391-394 ◽  
Author(s):  
Malgorzata I. Srebniak ◽  
Gizela G. Trapp ◽  
Angelika K. Wawrzkiewicz ◽  
Wojciech Kaźmierczak ◽  
Andrzej K. Wiczkowski

An increased number of chromosome plates can be obtained by use of calyculin A (CLA). CLA is an inhibitor of protein phosphatases (type 1 and type 2A serine/threonine). Inactivation of these phosphatases leads to premature chromosome condensation (PCC) in all phases of the cell cycle; thus, it is possible to investigate both metaphase and G2-PCC chromosomes. Amniotic fluid (AF) cultures were treated with calyculin A (CLA). GTG banding was obtained. Using this method it is possible to investigate all cell cycle phases, GTG banding, chromosomal breaks, and rates of PCD on the same preparation. Analyses of AF cultures treated with CLA allow complex studies on fetal genetic material. This work presents potential usefulness of CLA for cytogenetic prenatal diagnosis.

2006 ◽  
Vol 6 ◽  
pp. 1174-1190 ◽  
Author(s):  
Vasiliki I. Hatzi ◽  
Georgia I. Terzoudi ◽  
Christina Paraskevopoulou ◽  
Vasilios Makropoulos ◽  
Demetrios P. Matthopoulos ◽  
...  

Nowadays, there is a constantly increasing concern regarding the mutagenic and carcinogenic potential of a variety of harmful environmental factors to which humans are exposed in their natural and anthropogenic environment. These factors exert their hazardous potential in humans' personal (diet, smoking, pharmaceuticals, cosmetics) and occupational environment that constitute part of the anthropogenic environment. It is well known that genetic damage due to these factors has dramatic implications for human health. Since most of the environmental genotoxic factors induce arrest or delay in cell cycle progression, the conventional analysis of chromosomes at metaphase may underestimate their genotoxic potential. Premature Chromosome Condensation (PCC) induced either by means of cell fusion or specific chemicals, enables the microscopic visualization of interphase chromosomes whose morphology depends on the cell cycle stage, as well as the analysis of structural and numerical aberrations at the G1 and G2 phases of the cell cycle. The PCC has been successfully used in problems involving cell cycle analysis, diagnosis and prognosis of human leukaemia, assessment of interphase chromosome malformations resulting from exposure to radiation or chemicals, as well as elucidation of the mechanisms underlying the conversion of DNA damage into chromosomal damage. In this report, particular emphasis is given to the advantages of the PCC methodology used as an alternative to conventional metaphase analysis in answering questions in the fields of radiobiology, biological dosimetry, toxicogenetics, clinical cytogenetics and experimental therapeutics.


2020 ◽  
Vol 21 (2) ◽  
pp. 446 ◽  
Author(s):  
Adrián Campos ◽  
Andrés Clemente-Blanco

Cells are constantly suffering genotoxic stresses that affect the integrity of our genetic material. Genotoxic insults must be repaired to avoid the loss or inappropriate transmission of the genetic information, a situation that could lead to the appearance of developmental abnormalities and tumorigenesis. To combat this threat, eukaryotic cells have evolved a set of sophisticated molecular mechanisms that are collectively known as the DNA damage response (DDR). This surveillance system controls several aspects of the cellular response, including the detection of lesions, a temporary cell cycle arrest, and the repair of the broken DNA. While the regulation of the DDR by numerous kinases has been well documented over the last decade, the complex roles of protein dephosphorylation have only recently begun to be investigated. Here, we review recent progress in the characterization of DDR-related protein phosphatases during the response to a DNA lesion, focusing mainly on their ability to modulate the DNA damage checkpoint and the repair of the damaged DNA. We also discuss their protein composition and structure, target specificity, and biochemical regulation along the different stages encompassed in the DDR. The compilation of this information will allow us to better comprehend the physiological significance of protein dephosphorylation in the maintenance of genome integrity and cell viability in response to genotoxic stress.


2009 ◽  
Vol 25 (3) ◽  
pp. 220-228
Author(s):  
J. W. J. Bergs ◽  
J. W. J. Bergs ◽  
R. Ten Cate ◽  
H. M. Rodermond ◽  
P. A. Jaarsma ◽  
...  

1996 ◽  
Vol 270 (3) ◽  
pp. C898-C902 ◽  
Author(s):  
T. Krarup ◽  
P. B. Dunham

Osmotic swelling of dog and other mammalian erythrocytes activates Cl-dependent K transport, K-Cl cotransport. This activation can be abolished by nanomolar concentrations of calyculin, a potent inhibitor of serine-threonine protein phosphatases. Therefore, K-Cl cotransport is probably activated by dephosphorylation by a type 1 and/or type 2A protein phosphatase (PP-1 and PP-2A, respectively). This was tested directly by incorporating exogenous protein phosphatases into resealed ghosts made from dog erythrocytes previously exposed to calyculin. K-Cl cotransport was nearly completely inhibited in the ghosts. Incorporation of PP-1 reconstituted K-Cl cotransport. Maximal reconstitution was up to 90% of the control flux in the ghosts and 0.1 U PP-1/ml lysate gave half-maximal reconstitution of cotransport. In contrast, PP-2A had no effect. This result with PP-1 provides direct evidence that K-Cl cotransport is activated by PP-1 in dog erythrocytes. Half-maximal activation of K-Cl cotransport required approximately 180 molecules of PP-1 per ghost.


2020 ◽  
Vol 193 (6) ◽  
pp. 560 ◽  
Author(s):  
Mingzhu Sun ◽  
Jayne Moquet ◽  
Stephen Barnard ◽  
David Lloyd ◽  
Elizabeth Ainsbury

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