Nn. Khodarev et al., LINE L1 retrotransposable element is targeted during the initial stages ofapoptotic DNA fragmentation, J CELL BIOC, 79(3), 2000, pp. 486-495
Using a directional cloning strategy, DNA sequence information was obtained
corresponding to the site of early radiation-induced apoptotic DNA fragmen
tation within the human lymphoblastoid cell line TK6. Data were obtained fr
om 88 distinct clones comprising approximately 65 kbp of sequenced material
. Analysis of all cloned material showed that sequences in the 10 bp immedi
ately adjacent to the cleavage sites were enriched in short oligoT tracts.
The proportion of repetitive DNA within the entire cloned material was foun
d to be within the normal range. However the distribution of Alu and LINE r
epetitive DNA were biased to positions at or adjacent to the apoptotic clea
vage site. In particular, a non-random distribution of five cleavage sites
was found clustered within the second ORF of the LINE L1 that partially ove
rlapped with two binding sites for the nuclear matrix-associated protein SA
TB1. Three other clones, containing alpha satellite elements, were also lin
ked to a DNA matrix binding function. These data indicate that the site of
chromatin loop formation at the nuclear matrix may be a specific target for
early DNA fragmentation events during apoptosis. (C) 2000 Wiley-Liss, Inc.