Conserved nucleoprotein structure at the ends of vertebrate and invertebrate chromosomes.
Proc Natl Acad Sci U S A
; 92(6): 2393-7, 1995 Mar 14.
Article
in En
| MEDLINE
| ID: mdl-7892278
ABSTRACT
Eukaryotic chromosomes terminate with telomeres, nucleoprotein structures that are essential for chromosome stability. Vertebrate telomeres consist of terminal DNA tracts of sequence (TTAGGG)n, which in rat are predominantly organized into nucleosomes regularly spaced by 157 bp. To test the hypothesis that telomeres of other animals have nucleosomes, we compared telomeres from eight vertebrate tissues and cell cultures, as well as two tissues from an invertebrate. All telomeres have substantial tracts of (TTAGGG)n comprising 0.01-0.2% of the genome. All telomeres are long (20-100 kb), except for those of sea urchin, human, and some chicken chromosomes, which are 3-10 kb in length. All of the animal telomeres contained nucleosome arrays, consistent with the original hypothesis. The telomere repeat lengths vary from 151 to 205 bp, seemingly uncorrelated with telomere size, regularity of nucleosome spacing, species, or state of differentiation but surprisingly correlated with the repeat of bulk chromatin within the same cells. The telomere nucleosomes were consistently approximately 40 bp smaller than bulk nucleosomes. Thus, animal telomeres have highly conserved sequences and unusually short nucleosomes with cell-specific structure.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Vertebrates
/
DNA
/
Chromosomes
/
Invertebrates
/
Nucleoproteins
Limits:
Animals
/
Humans
Language:
En
Journal:
Proc Natl Acad Sci U S A
Year:
1995
Document type:
Article