Chromatin isolated from viable human PBLs contains DNA fragmented to ≥ 50 kb

Gábor Szabó, Zsolt Bacsó

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Abstract

Massive chromatin fragmentation (around 50 kb, to several hundred kb) is observed in nuclear lysates of human peripheral blood lymphocytes (PBLs) upon their treatment with nuclease free protein-denaturants. There is a consistent variation in the fragment size distributions that parallels the proliferative activity of the cells. Predominantly ~50 kb fragmentation is exhibited in samples from cells immunsuppressed via CD4 crosslinking, as opposed to the heterogeneous, higher molecular weight DNA of anti-TcR/CD3-, phytohemagglutininor concanavalin A-stimulated cells. Tritiated thymidine incorporated into DNA in the latter cultures can be detected in the ~50 kb band. Direct lysis of agarose embedded, live cells in alkali + detergent also yields fragmented DNA, with a single-strand size of ≥ 50 kb. These data suggest that (i) the cells yielding fragmented DNA were alive at the time of DNA extraction, (ii) either regularly arranged, preformed nicks or hypersensitive sites may be present at every roughly 50-100 kb in the chromatin of PBLs, (iii) these sites or the fragmentation mechanism acting upon them, appear to be regulated in concert with the transit of cells between the resting and proliferative compartments.

Original languageEnglish
Pages (from-to)237-241
Number of pages5
JournalCell Death and Differentiation
Volume3
Issue number2
Publication statusPublished - Jan 1 1996

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Keywords

  • Apoptosis
  • CD4
  • Chromatin fragmentation
  • Peripheral blood lymphocytes

ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology

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