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Complex telomere-associated repeat units in members of the genus Chironomus evolve from sequences similar to simple telomeric repeats

Nielsen, Lena and Edström, J-E. (1993) In Molecular and Cellular Biology 13(3). p.1583-1589
Abstract
The dipteran Chironomus tentans has complex tandemly repeated 350-bp DNA sequences at or near the chromosome ends. As in Drosophila melanogaster, short simple repeats with cytosines and guanines in different strands have never been observed. We were therefore interested in learning whether the Chironomus repeats could have evolved from simple sequence telomeric DNA, which might suggest that they constitute a functional equivalent. We screened for repeat units with evolutionarily ancient features within the tandem arrays and recovered two clones with a less-evolved structure. Sequence analysis reveals that the present-day 350-bp unit probably evolved from a simpler 165-bp unit through the acquisition of transposed sequences. The 165-bp unit... (More)
The dipteran Chironomus tentans has complex tandemly repeated 350-bp DNA sequences at or near the chromosome ends. As in Drosophila melanogaster, short simple repeats with cytosines and guanines in different strands have never been observed. We were therefore interested in learning whether the Chironomus repeats could have evolved from simple sequence telomeric DNA, which might suggest that they constitute a functional equivalent. We screened for repeat units with evolutionarily ancient features within the tandem arrays and recovered two clones with a less-evolved structure. Sequence analysis reveals that the present-day 350-bp unit probably evolved from a simpler 165-bp unit through the acquisition of transposed sequences. The 165-bp unit contains DNA with a highly biased distribution of cytosine and guanine between the two strands, although with the ratios inverted in two minor parts of the repeat. It is largely built up of short degenerate subrepeats for which most of the sequence can be reconstructed. The consensus for the subrepeat sequence is similar to the simple telomeric repeat sequences of several kinds of eukaryotes. We propose that the present-day unit has evolved from telomeric, simple sequence, asymmetric DNA from which it has retained some original sequence features and possibly functions. (Less)
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author
publishing date
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Contribution to journal
publication status
published
subject
in
Molecular and Cellular Biology
volume
13
issue
3
pages
1583 - 1589
publisher
American Society for Microbiology
ISSN
0270-7306
language
English
LU publication?
no
id
900de40b-564c-46df-a74b-5c602b1992f4 (old id 30959)
date added to LUP
2007-06-19 14:34:33
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2016-06-29 08:57:14
@article{900de40b-564c-46df-a74b-5c602b1992f4,
  abstract     = {The dipteran Chironomus tentans has complex tandemly repeated 350-bp DNA sequences at or near the chromosome ends. As in Drosophila melanogaster, short simple repeats with cytosines and guanines in different strands have never been observed. We were therefore interested in learning whether the Chironomus repeats could have evolved from simple sequence telomeric DNA, which might suggest that they constitute a functional equivalent. We screened for repeat units with evolutionarily ancient features within the tandem arrays and recovered two clones with a less-evolved structure. Sequence analysis reveals that the present-day 350-bp unit probably evolved from a simpler 165-bp unit through the acquisition of transposed sequences. The 165-bp unit contains DNA with a highly biased distribution of cytosine and guanine between the two strands, although with the ratios inverted in two minor parts of the repeat. It is largely built up of short degenerate subrepeats for which most of the sequence can be reconstructed. The consensus for the subrepeat sequence is similar to the simple telomeric repeat sequences of several kinds of eukaryotes. We propose that the present-day unit has evolved from telomeric, simple sequence, asymmetric DNA from which it has retained some original sequence features and possibly functions.},
  author       = {Nielsen, Lena and Edström, J-E.},
  issn         = {0270-7306},
  language     = {eng},
  number       = {3},
  pages        = {1583--1589},
  publisher    = {American Society for Microbiology},
  series       = {Molecular and Cellular Biology},
  title        = {Complex telomere-associated repeat units in members of the genus Chironomus evolve from sequences similar to simple telomeric repeats},
  volume       = {13},
  year         = {1993},
}