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Proteolytic cleavage of HsRad51 during apoptosis
Author(s) -
Flygare Jenny,
Armstrong Robert C,
Wennborg Anders,
Orsan Solweig,
Hellgren Dennis
Publication year - 1998
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(98)00433-5
Subject(s) - jurkat cells , poly adp ribose polymerase , microbiology and biotechnology , apoptotic dna fragmentation , apoptosis , cleavage (geology) , dna fragmentation , biology , dna , polymerase , programmed cell death , biochemistry , t cell , genetics , paleontology , immune system , fracture (geology)
The Rad51 gene of Saccharomyces cerevisiae is required for genetic recombination and recombinational repair of DNA strand breaks. In higher eukaryotes Rad51 is essential for embryonic development, and is involved in cell proliferation and DNA repair. Here we show that human Rad51 (HsRad51) is proteolytically cleaved during apoptosis in two T‐lymphocyte cell lines, Jurkat and PFI‐285. Apoptosis was induced by camptothecin or anti‐Fas monoclonal antibody (anti‐Fas mAb). HsRad51 was cleaved with similar kinetics as human poly(ADP‐ribose) polymerase (HsPARP) after treatment with either agent. The time course of cleavage coincided with internucleosomal DNA fragmentation. The HsRad51 fragments observed in apoptotic cells were identical to those generated from in vitro translated (IVT) HsRad51 exposed to activated Jurkat S‐100 extract in a cell‐free system. In each case, cleavage of HsRad51 was abolished by acetyl‐Asp‐Glu‐Val‐Asp‐aldehyde (Ac‐DEVD‐CHO). However, cleavage of IVT HsRad51 could not be demonstrated using purified caspase‐2, ‐3 or ‐6 to ‐10, and the identity of the responsible protease thus remains to be determined. In summary, we have shown that HsRad51 belongs to a group of repair proteins, including PARP and DNA‐dependent protein kinase, which are specifically cleaved during the execution phase of apoptosis.