Sequence comparison of human and yeast telomeres identifies structurally distinct subtelomeric domains.
We have sequenced and compared DNA from the ends of three human chromosomes: 4p, 16p and 22q. In all cases the pro-terminal regions are subdivided by degenerate (TTAGGG)n repeats into distal and proximal sub-domains with entirely different patterns of homology to other chromosome ends. The distal regions contain numerous, short (<2 kb) segments of interrupted homology to many other human telomeric regions. The proximal regions show much longer (approximately 10-40 kb) uninterrupted homology to a few chromosome ends. A comparison of all yeast subtelomeric regions indicates that they too are subdivided by degenerate TTAGGG repeats into distal and proximal sub-domains with similarly different patterns of identity to other non-homologous chromosome ends. Sequence comparisons indicate that the distal and proximal sub-domains do not interact with each other and that they interact quite differently with the corresponding regions on other, non-homologous, chromosomes. These findings suggest that the degenerate TTAGGG repeats identify a previously unrecognized, evolutionarily conserved boundary between remarkably different subtelomeric domains.
Flint
J
J
Institute of Molecular Medicine, John Radcliffe Hospital, Headington, Oxford, UK. jf@worf.molbiol.ox.ac.uk
Bates
G P
GP
Clark
K
K
Dorman
A
A
Willingham
D
D
Roe
B A
BA
Micklem
G
G
Higgs
D R
DR
Louis
E J
EJ
D001483:Base Sequence; D018244:Chromosomes, Artificial, Yeast; D006801:Humans; D008969:Molecular Sequence Data; D012441:Saccharomyces cerevisiae / Q000235:genetics; D016615:Telomere