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The terminal DNA structure of mammalian chromosomes
Author(s) -
McElligott Richard,
Wellinger Raymund J.
Publication year - 1997
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/16.12.3705
Subject(s) - biology , telomere , chromosome , centromere , dna , eukaryotic chromosome fine structure , genetics , repeated sequence , microbiology and biotechnology , genome , gene
In virtually all eukaryotic organisms, telomeric DNA is composed of a variable number of short direct repeats. While the primary sequence of telomeric repeats has been determined for a great variety of species, the actual physical DNA structure at the ends of a bona fide metazoan chromosome with a centromere is unknown. It is shown here that an overhang of the strand forming the 3′ ends of the chromosomes, the G‐rich strand, is found at mammalian chromosome ends. Moreover, on at least some telomeres, the overhangs are ≥ 45 bases long. Such surprisingly long overhangs were present on chromosomes derived from fully transformed tissue culture cells and normal G 0 ‐arrested peripheral leukocytes. Thus, irrespective of whether the cells were actively dividing or arrested, a very similar terminal DNA arrangement was found. These data suggest that the ends of mammalian and possibly all vertebrate chromosomes consist of an overhang of the G‐rich strand and that these overhangs may be considerably larger than previously anticipated.