An evolutionary change in telomere sequence motif within the plant section Asparagales had significance for telomere nucleoprotein complexes
Language English Country Switzerland Media print
Document type Comparative Study, Journal Article, Research Support, Non-U.S. Gov't
PubMed
15305069
DOI
10.1159/000079584
PII: 79584
Knihovny.cz E-resources
- MeSH
- Arabidopsis genetics MeSH
- Cell Extracts chemistry pharmacology MeSH
- Cell Nucleus chemistry genetics MeSH
- Chromatin genetics MeSH
- Chromosomal Proteins, Non-Histone genetics pharmacology MeSH
- Chromosomes, Plant genetics metabolism MeSH
- DNA, Plant genetics metabolism MeSH
- Guanine metabolism MeSH
- Humans MeSH
- Liliaceae cytology enzymology genetics MeSH
- Plant Leaves cytology MeSH
- Magnoliopsida genetics MeSH
- Evolution, Molecular * MeSH
- Nucleoproteins genetics MeSH
- Repetitive Sequences, Nucleic Acid genetics MeSH
- Plant Proteins genetics metabolism pharmacology MeSH
- Scilla cytology enzymology genetics MeSH
- Telomerase antagonists & inhibitors MeSH
- Telomere enzymology genetics metabolism MeSH
- Base Composition genetics MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Comparative Study MeSH
- Names of Substances
- Cell Extracts MeSH
- Chromatin MeSH
- Chromosomal Proteins, Non-Histone MeSH
- DNA, Plant MeSH
- Guanine MeSH
- Nucleoproteins MeSH
- Plant Proteins MeSH
- Telomerase MeSH
In association with a phylogenetic tree of Asparagales, our previous results showed that a distinct clade included plant species where the ancestral, Arabidopsis-type of telomeric repeats (TTTAGGG)n had been partially, or fully, replaced by the human-type telomeric sequence (TTAGGG)n. Telomerases of these species synthesize human repeats with a high error rate in vitro. Here we further characterize the structure of telomeres in these plants by analyzing the overall arrangement of major and minor variants of telomeric repeats using fluorescence in situ hybridization on extended DNA strand(s). Whilst the telomeric array is predominantly composed of the human variant of the repeat, the ancestral, Arabidopsis-type of telomeric repeats was ubiquitously observed at one of the ends and/or at intercalary positions of extended telomeric DNAs. Another variant of the repeat typical of Tetrahymena was observed interspersed in about 20% of telomerics. Micrococcal nuclease digestions indicated that Asparagales plants with a human-type of telomere have telomeric DNA organised into nucleosomes. However, unexpectedly, the periodicity of the nucleosomes is not significantly shorter than bulk chromatin as is typical of telomeric chromatin. Using electrophoretic mobility shift assays we detected in Asparagales plants with a human type of telomere a 40-kDa protein that forms complexes with both Arabidopsis- and human-type G-rich telomeric strands. However, the protein shows a higher affinity to the ancestral Arabidopsis-type sequence. Two further proteins were found, a 25-kDa protein that binds specifically to the ancestral sequence and a 15-kDa protein that binds to the human-type telomeric repeat. We discuss how the organisation of the telomere repeats in Asparagales may have arisen and stabilised the new telomere at the point of mutation.
Cytogenet Genome Res. 2005;109(4):535 PubMed Syrova, E [corrected to Sýkorová, E]
References provided by Crossref.org
Dynamic evolution of telomeric sequences in the green algal order Chlamydomonadales
Asparagales telomerases which synthesize the human type of telomeres
Telomeres in evolution and evolution of telomeres
