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001-es BibID:	BIBFORM004663
035-os BibID:	(scopus)0343962249 (wos)000087812700009
Első szerző:	Gál István (sebész)
Cím:	Protease-elicited TUNEL positivity of non-apoptotic fixed cells / Gal, I., Varga, T., Szilagyi, I., Balazs, M., Schlammadinger, J., Szabo, G.
Dátum:	2000
Megjegyzések:	The appearance of free DNA ends in the chromatin is usually considered an indication of advanced apoptosis. Unexpectedly, the nuclei of non-apoptotic cells derived from mouse thymuses could be specifically labeled by terminal transferase after proteinase K treatment of the fixed, cytocentrifuged samples. Artifactual mechanical or contaminating nucleolytic factors have been ruled out as players in the generation of free DNA ends. The phenomenon was detected in both formaldehyde- and ethanol-fixed specimens, in agarose-embedded fixed cells, and in chromatin spreads. By urea-agarose gel electrophoresis, the average single-strand size of the DNA molecules carrying the free ends was found between 50 and 250 kb. We suggest that ss discontinuities preexisting in the fixed normal cells are unmasked by protease treatment eliciting TUNEL (terminal transferase-mediated nick end-labeling) positivity.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk Animals Apoptosis Artifacts Biophysics Cells Chromatin cytology Dna DNA Fragmentation Electrophoresis, Agar Gel Endopeptidase K Formaldehyde Hungary In Situ Nick-End Labeling metabolism Mice Mice, Inbred BALB C physiology Research Support Thymus Gland
Megjelenés:	The Journal of Histochemistry and Cytochemistry. - 48 : 7 (2000), p. 963-970. -
További szerzők:	Varga Tamás (1971-) (biológus) Szilágyi Ildikó (orvos) Balázs Margit (1952-) (sejtbiológus, molekuláris genetikus) Schlammadinger József (1938-) (kutató orvos) Szabó Gábor (1953-) (biofizikus)
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001-es BibID:	BIBFORM004740
035-os BibID:	(WOS)000184609400011 (scopus)12444317206
Első szerző:	Szilágyi Ildikó (orvos)
Cím:	Non-random features of loop-size chromatin fragmentation / Szilagyi, I., Varga, T., Szekvolgyi, L., Hegedus, E., Goda, K., Kaczur, V., Bacso, Z., Nakayama, Y., Posafi, J., Pongor, S., Szabo, G.
Dátum:	2003
ISSN:	730-2312 (Print)
Megjegyzések:	Upon isolation of DNA from normal eukaryotic cells by standard methods involving extensive proteolytic treatment, a rather homogeneous population of loop-size, double-stranded DNA fragments is regularly obtained. These DNA molecules can be efficiently end-labeled by the DNA polymerase I Klenow fragment, as well as by a 3'- to -5'-exonuclease-free Klenow enzyme, but not by terminal transferase (TdT) unless the ends have been filled up by Klenow, suggesting that dominantly 5' protruding termini are generated upon fragmentation. The filled-up termini were used for cloning the distal parts of the approximately 50 kb fragments. BLAST analysis of the sequence of several clones allowed us to determine the sequence of the non-cloned side of the breakpoints. Comparison of 25, 600 bp-long breakpoint sequences demonstrated prevalence of repetitive elements. Consensus motives characteristic of the breakpoint sequences have been identified. Several sequences exhibit peculiar computed conformational characteristics, with sharp transition or center of symmetry located exactly at the breakpoint. Our data collectively suggest that chromatin fragmentation involves nucleolytic cleavages at fragile/hypersensitive sites delimiting loop-size fragments in a non-random manner. Interestingly, the sequence characteristics of the breakpoints are reminiscent of certain breakpoint cluster regions frequently subject to gene rearrangements.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk analysis Animals Base Sequence Biophysics Cells chemistry Chromatin Dna DNA Fragmentation DNA Nucleotidylexotransferase DNA Polymerase I Electrophoresis,Gel,Two-Dimensional Eukaryotic Cells HL-60 Cells Humans Hungary isolation and purification Jurkat Cells methods Mice Nih 3T3 Cells Prevalence Research Sequence Analysis,DNA Support egyetemen (Magyarországon) készült közlemény
Megjelenés:	Journal of Cellular Biochemistry. - 89 : 6 (2003), p. 1193-1205. -
További szerzők:	Varga Tamás (1971-) (biológus) Székvölgyi Lóránt (1977-) (biofizikus, biokémikus, sejtbiológus) Hegedűs Éva (1978-) (biofizikus) Goda Katalin (1969-) (biofizikus) Kaczur Viktória Bacsó Zsolt (1963-) (biofizikus) Nakayama, Yuji Pósafi János Pongor Sándor Szabó Gábor (1953-) (biofizikus)
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001-es BibID:	BIBFORM004654
035-os BibID:	(scopus)0344199417 (wos)000083351400015
Első szerző:	Varga Tamás (biológus)
Cím:	Single-strand breaks in agarose-embedded chromatin of nonapoptotic cells / Varga, T., Szilagyi, I., Szabo, G.
Dátum:	1999
Megjegyzések:	Loop-size chromatin fragmentation frequently observed upon apoptotic cell death is thought to be initiated by ss nicks. Here we show that the agarose-embedded, deproteinized chromatin of normal, non-apoptotic murine and human cells, as well as yeast protoplasts, falls apart to 50-300 kb ss fragments upon heat denaturation, as revealed by urea-TAE field-inversion agarose gel electrophoresis resolving ss and ds fragments alike. These data were in line with S1digestion experiments. The nicks (gaps) observed are best explained either by enzymatic cleavages occurring upon cell lysis instantaneously or by preexisting discontinuities becoming manifest upon heat denaturation. These discontinuities go unnoticed in the usual nondenaturaing circumstances but seem to be inevitably present in any DNA preparation. The loop-size ds DNA fragmentation in apoptosis may be based on these pre-existing or "ready-to-go" (upon cell lysis) ss discontinuities of the normal cellular chromatin
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk Animals Apoptosis Aspergillus Nuclease S1 Biophysics Cell Line Cells chemistry Chromatin Dna DNA Damage DNA Fragmentation DNA,Single-Stranded Electrophoresis, Agar Gel Electrophoresis, Gel, Pulsed-Field Heat Human Humans Hungary Mice Nucleic Acid Denaturation Research Saccharomyces cerevisiae Sepharose Support ultrastructure Urea
Megjelenés:	Biochemical and Biophysical Research Communications. - 264 : 2 (1999), p. 388-394. -
További szerzők:	Szilágyi Ildikó (orvos) Szabó Gábor (1953-) (biofizikus)
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