Search results

1

The DFF40/CAD endonuclease and its role in apoptosis.

100%

Widłak P.

|

2000

|

vol. 47

|

issue 4

1037-1044

EN

The sequential generation of large-scale DNA fragments followed by internucleosomal chromatin fragmentation is a biochemical hallmark of apoptosis. One of the nucleases primarily responsible for genomic DNA fragmentation during apoptosis is called DNA Fragmentation Factor 40 (DFF40) or Caspase-activated DNase (CAD). DFF40/CAD is a magnesium-dependent endonuclease specific for double stranded DNA that generates double strand breaks with 3'-hydroxyl ends. DFF40/CAD is activated by caspase-3 that cuts the nuclease's inhibitor DFF45/ICAD. The nuclease preferentially attacks chromatin in the internucleosomal linker DNA. However, the nuclease hypersensitive sites can be detected and DFF40/CAD is potentially involved in large-scale DNA fragmentation as well. DFF40/CAD-mediated DNA fragmentation triggers chromatin condensation that is another hallmark of apoptosis.

2

DNA microarrays, a novel approach in studies of chromatin structure.

100%

Widłak P.

|

vol. 51

|

issue 1

1-8

EN

The DNA microarray technology delivers an experimental tool that allows surveying expression of genetic information on a genome-wide scale at the level of single genes - for the new field termed functional genomics. Gene expression profiling - the primary application of DNA microarrays technology - generates monumental amounts of information concerning the functioning of genes, cells and organisms. However, the expression of genetic information is regulated by a number of factors that cannot be directly targeted by standard gene expression profiling. The genetic material of eukaryotic cells is packed into chromatin which provides the compaction and organization of DNA for replication, repair and recombination processes, and is the major epigenetic factor determining the expression of genetic information. Genomic DNA can be methylated and this modification modulates interactions with proteins which change the functional status of genes. Both chromatin structure and transcriptional activity are affected by the processes of replication, recombination and repair. Modified DNA microarray technology could be applied to genome-wide study of epigenetic factors and processes that modulate the expression of genetic information. Attempts to use DNA microarrays in studies of chromatin packing state, chromatin/DNA-binding protein distribution and DNA methylation pattern on a genome-wide scale are briefly reviewed in this paper.

3

Struktura chromatyny a powstawanie i naprawa uszkodzeń DNA

100%

Widłak P.

Kosmos

|

2002

|

vol. 51

|

issue 1

5-12

EN

Summary Chromatin structure modulates the rate of DNA damage formation and repair in different regions of eukaryotic genomes. Chromatin rearrangement takes place during repair to increase accessibility of damage to repair proteins. Activity of histone acetyltransferases and chromatin remodeling complexes seems to be essential for nucleosome rearrangement during repair. Once repair is completed, reconstitution of nucleosomes is required to recover primary chromatin structure. Such chromatin assembly is coupled to repair DNA synthesis. DNA damages induce some modifications to chromatin structure (e.g. phosphorylation of a histone H2A variant in response to DNA double-strand breaks). Such chromatin modifications may serve as signals recognized by DNA repair systems.

4

Characterization of a novel protein that specifically binds to DNA modified by N-acetoxy-acetylaminofluorene and cis-diamminedichloroplatinum

64%

Pietrowska M., Widłak P.

|

2005

|

vol. 52

|

issue 4

867-874

EN

Proteins recognizing DNA damaged by the chemical carcinogen N-acetoxy-acetylaminofluorene (AAAF) were analyzed in nuclear extracts from rat tissues, using a 36 bp oligonucleotide as a substrate and electrophoretic mobility shift and Southwestern blot assays. One major damage-recognizing protein was detected, whose amount was estimated as at least 105 copies per cell. Levels of this protein were similar in extracts from brain, kidney and liver, but much lower in extracts from testis. The affinity of the detected protein for DNA damaged by AAAF was about 70-fold higher than for undamaged DNA. DNA damaged by cis-diamminedichloroplatinum (cis-DDP), benzo(a)pyrene diolepoxide (BPDE) or UV-radiation also bound this protein with an increased affinity, the former more strongly and the latter two more weakly as compared to AAAF-damaged DNA. The detected AAAF/DDP-damaged-DNA-binding (AAAF/DDP-DDB) protein had a molecular mass of about 25 kDa and was distinct from histone H1 or HMGB proteins, which are known to have a high affinity for cis-DDP-damaged DNA. The level of this damage-recognizing protein was not affected in rats treated with the carcinogen 2-acetylaminofluorene. The activity of an AAAF/DDP-DDB protein could also be detected in extracts from mouse liver cells but not from the Hep2G human hepatocellular carcinoma.

5

High mobility group proteins stimulate DNA cleavage by apoptotic endonuclease DFF40/CAD due to HMG-box interactions with DNA

64%

Kalinowska-Herok M., Widłak P.

|

2008

|

vol. 55

|

issue 1

21-26

EN

The DFF40/CAD endonuclease is primarily responsible for internucleosomal DNA cleavage during the terminal stages of apoptosis. It has been previously demonstrated that the major HMG-box-containing chromatin proteins HMGB1 and HMGB2 stimulate naked DNA cleavage by DFF40/CAD. Here we investigate the mechanism of this stimulation and show that HMGB1 neither binds to DFF40/CAD nor enhances its ability for stable binding to DNA. Comparison of the stimulatory activities of different truncated forms of HMGB1 protein indicates that a structural array of two HMG-boxes is required for such stimulation. HMG-boxes are known to confer specific local distortions of DNA structure upon binding. Interestingly, the presence of DNA strand cross-links formed by cisplatin or transplatin, which may somehow mimic distortions induced by HMG-boxes, also affects DNA cleavage by the nuclease. The data presented suggest that changes induced in DNA conformation upon HMG-box binding makes the substrate more accessible to cleavage by DFF40/CAD nuclease and thus may contribute to preferential linker DNA cleavage during apoptosis.

6

Formation and removal of DNA adducts in liver of rats treated with hepatocarcinogens 2-aminofluorene or 2-acetylaminofluorene

63%

Widłak P., Rzeszowska-Wolny J.

Acta Biochimica Polonica

|

1991

|

vol. 38

|

issue 1

145-150

7

52%

Widłak P., Rogoliński J., Rzeszowska-Wolny J.

|

11

High levels of bulky DNA adducts in human sperm correlate with impaired fertility.

52%

Horak S., Polańska J., Widłak P.

|

2003

|

vol. 50

|

issue 1

197-203

EN

Progressive decline in fertility and sperm quality has been reported over the last few decades, especially in industrialized nations. It has been proposed that exposure to factors that induce damage in DNA of spermatogenic cells may significantly contribute to impaired fertility. Here, the 32P-postlabelling method was used to analyze the levels of bulky DNA adducts in sperm cells in a group of 179 volunteers, either healthy subjects or patients with an impaired fertility. The levels of DNA adducts were 1.35-fold higher in the infertile group as compared to healthy individuals (P = 0.012). Similarly, a significant negative correlation between the levels of DNA adducts and measures of semen quality (sperm concentration and motility) has been observed (P Ł 0.001). In addition, the levels of bulky DNA adducts in sperm cells positively correlates with amounts of leukocytes in semen, which were significantly higher in semen of infertile subjects.

12

Interactions of rat repetitive sequence MspI8 with nuclear matrix proteins during spermatogenesis

51%

Rogoliński J., Widłak P., Rzeszowska-Wolny J.

Acta Biochimica Polonica

|

1996

|

vol. 43

|

issue 2

39%

Jelonek K., Walaszczyk A., Gabryś D., Pietrowska M., Kanthou C., Widłak P.

|

2011

|

vol. 58

|

issue 3

397-404

EN

Cardiovascular disease is recognized as an important clinical problem in radiotherapy and radiation protection. However, only few radiobiological models relevant for assessment of cardiotoxic effects of ionizing radiation are available. Here we describe the isolation of mouse primary cardiac endothelial cells, a possible target for cardiotoxic effects of radiation. Cells isolated from hearts of juvenile mice were cultured and irradiated in vitro. In addition, cells isolated from hearts of locally irradiated adult animals (up to 6 days after irradiation) were tested. A dose-dependent formation of histone γH2A.X foci was observed after in vitro irradiation of cultured cells. However, such cells were resistant to radiation-induced apoptosis. Increased levels of actin stress fibres were observed in the cytoplasm of cardiac endothelial cells irradiated in vitro or isolated from irradiated animals. A high dose of 16 Gy did not increase permeability to Dextran in monolayers formed by endothelial cells. Up-regulated expression of Vcam1, Sele and Hsp70i genes was detected after irradiation in vitro and in cells isolated few days after irradiation in vivo. The increased level of actin stress fibres and enhanced expression of stress-response genes in irradiated endothelial cells are potentially involved in cardiotoxic effects of ionizing radiation.

19

TNFα-induced activation of NFκB protects against UV-induced apoptosis specifically in p53-proficient cells

39%

Szołtysek K., Pietranek K., Kalinowska-Herok M., Pietrowska M., Kimmel M., Widłak P.

|

2008

|

vol. 55

|

issue 4

741-748

EN

The signaling pathways that depend on p53 or NFκB transcription factors are essential components of cellular responses to stress. In general, p53 is involved in either activation of cell cycle arrest or induction of apoptosis, while NFκB exerts mostly anti-apoptotic functions; both regulatory pathways apparently interfere with each other. Here we aimed to analyze the effects of NFκB activation on DNA damage-induced apoptosis, either p53-dependent or p53-independent, in a set of human cell lines. Four cell lines, HCT116 and RKO colon carcinoma, NCI-H1299 lung carcinoma and HL60 myeloblastoma, each of them in two congenic variants either containing or lacking transcriptionally competent p53, were used. Cells were incubated with TNFα cytokine to activate NFκB and then treated with ultraviolet or ionizing radiation to induce apoptosis, which was assessed by measurement of the sub-G1 cell fraction. We observed that treatment with TNFα resulted in a significant reduction in the frequency of apoptotic cells in UV-irradiated p53-proficient lines (with exception of the UV-resistant NCI-H1299 cells). This anti-apoptotic effect was lost when cells were pretreated with parthenolide, an inhibitor of NFκB activation. In marked contrast, TNFα-pretreatment of p53-deficient lines resulted in an increased frequency of apoptotic cells after UV irradiation (with exception of HL60 cells). Such anti- and pro-apoptotic influence of TNFα was less obvious in cells treated with ionizing radiation. The data clearly indicates functional interference of both signaling pathways upon the damage-induced apoptotic response, yet the observed effects are both cell type- and stimulus-specific.

20

Nucleosomes and regulation of gene expression. Structure of the HIV-1 5'LTR

38%

Widłak P., Garrard W. T.

Acta Biochimica Polonica

|

1998

|

vol. 45

|

issue 1

209-219

Refine search results

The DFF40/CAD endonuclease and its role in apoptosis.

DNA microarrays, a novel approach in studies of chromatin structure.

Struktura chromatyny a powstawanie i naprawa uszkodzeń DNA

Characterization of a novel protein that specifically binds to DNA modified by N-acetoxy-acetylaminofluorene and cis-diamminedichloroplatinum

High mobility group proteins stimulate DNA cleavage by apoptotic endonuclease DFF40/CAD due to HMG-box interactions with DNA

Formation and removal of DNA adducts in liver of rats treated with hepatocarcinogens 2-aminofluorene or 2-acetylaminofluorene

DNA adducts in environmental, occupational and life-style studies in human biomonitoring

Mitochondrial transcription factor A is the major protein in rodent hepatocytes that recognizes DNA lesions induced by N-acetoxy-acetylaminofluorene

Detection of damage-recognition proteins from human lymphocytes.

Interactions of the matrix attachment region of DNA with the matrix proteins from the copper preincubated liver nuclei

High levels of bulky DNA adducts in human sperm correlate with impaired fertility.

Interactions of rat repetitive sequence MspI8 with nuclear matrix proteins during spermatogenesis

DNA and proteins of the nuclear matrix are the main targets of benzo[a]pyrene's action in rat hepatocytes

Damaged DNA-binding proteins: recognition of N-acetoxy-acetylaminofluorene-induced DNA adducts

Characterization of DNA sequences localized 11 to 17.5 kb upstream of the chicken embryonic π-globin gene

Effects of the hepatocarcinogen 2-aminofluorene on RNA synthesis in rat liver

Reconstitution of UV-damaged DNA into chromatin using Xenopus oocyte extracts

Cardiac endothelial cells isolated from mouse heart - a novel model for radiobiology

TNFα-induced activation of NFκB protects against UV-induced apoptosis specifically in p53-proficient cells

Nucleosomes and regulation of gene expression. Structure of the HIV-1 5'LTR