Organization of telomeric and subtelomeric chromatin in the higher plant Nicotiana tabacum

Fajkus, Jiřı́; Kovařı́k, Aleš; Královics, Róbert; Bezděk, M.

doi:10.1007/bf00290355

Cited by 161 publications

(153 citation statements)

References 19 publications

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“…These lengths are similar to those observed in tobacco leaf cells (40-160 kb, Fig. 1C; see also [10,11]), the only significant difference being an overrepresentation of shorter TRFs in TBY-2 cells where their average length is about 50 kb, in comparison to tobacco leaf cells where most TRFs fall between 90 and 130 kb. The TRF lengths were stable over the 6 month period of culture (Fig.…”

Section: Trf Lengths In Tb Y-2 Cellssupporting

confidence: 84%

Telomerase activity in plant cells

1996

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Telomerase is a ribonucleoprotein enzyme which elongates the G-rich strand of telomeric DNA to compensate for the progressive reduction in its length due to incomplete replication of chromosome ends, which in human somatic cells leads to cell cycle arrest upon shortening of telomeres to a critical length. To examine the possible involvement of telomerase in metabolism of plant genetic material, we used cells of Nicotiana tabacum strain TBY-2, a stable long-term culture which has kept a constant pattern of restriction fragments from chromosome termini during its 6 month period of cultivation in our laboratory. In a direct assay for telomerase, a 5' end-labeled plant telomeric oligonueleotide S'(TTTAGGG)6 3' was elongated in a TBY-2 cell extract, showing a pausing pattern which is a characteristic feature of telomerases from other organisms. The elongation was inhibited by RNase A pretreatment of the extract. We conclude that plant cells possess telomerase which is used for maintenance of their telomeres.

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Section: Trf Lengths In Tb Y-2 Cellssupporting

confidence: 84%

Telomerase activity in plant cells

1996

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“…The length of the telomere tract varies considerably among different species of land plants and green algae, ranging from 0.5 kb in Chlorella vulgaris to over 150 kb in tobacco (Nicotiana tabacum; Fajkus et al, 1995;Higashiyama et al, 1995). In most Arabidopsis ecotypes, telomeres span 2 to 5 kb .…”

Section: Telomere Length and Composition In P Patensmentioning

confidence: 99%

Protection of Telomeres 1 Is Required for Telomere Integrity in the Moss Physcomitrella patens

et al. 2010

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In vertebrates, the single-stranded telomeric DNA binding protein Protection of Telomeres 1 (POT1) shields chromosome ends and prevents them from eliciting a DNA damage response. By contrast, Arabidopsis thaliana encodes two divergent full-length POT1 paralogs that do not exhibit telomeric DNA binding in vitro and have evolved to mediate telomerase regulation instead of chromosome end protection. To further investigate the role of POT1 in plants, we established the moss Physcomitrella patens as a new model for telomere biology and a counterpoint to Arabidopsis. The sequence and architecture of the telomere tract is similar in P. patens and Arabidopsis, but P. patens harbors only a single-copy POT1 gene. Unlike At POT1 proteins, Pp POT1 efficiently bound single-stranded telomeric DNA in vitro. Deletion of the P. patens POT1 gene resulted in the rapid onset of severe developmental defects and sterility. Although telomerase activity levels were unperturbed, telomeres were substantially shortened, harbored extended G-overhangs, and engaged in end-to-end fusions. We conclude that the telomere capping function of POT1 is conserved in early diverging land plants but is subsequently lost in Arabidopsis.

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“…Telomere length in various plants has been reported: 2.5 kb in Arabidopsis thaliana [20]; 4.5 kb at most in Melandrium album [28]; 60 to 160 kb (in most cases 90 to 130 kb) in Nicotiana tabacum [6]; and 1.8 to 40.0 kb in maize [4]. Does telomere length change in different cells?…”

Section: Introductionmentioning

confidence: 99%

Comparative Analysis of Rice Genome Sequence to Understand the Molecular Basis of Genome Evolution

Mizuno

Sasaki

et al. 2008

Rice

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Accurate sequencing of the rice genome has ignited a passion for elucidating mechanism for sequence diversity among rice varieties and species, both in proteincoding regions and in genomic regions that are important for chromosome functions. Here, we have shown examples of sequence diversity in genic and non-genic regions. Sequence analysis of chromosome ends has revealed that there is diversity in both sequences and distribution in the region of telomere repeat arrays, from chromosome to chromosome, within a plant. Detailed study has allowed us to speculate the mechanism of generation of these arrays. Sequence analysis using various cultivated and wild rice of the sd1 gene, which contributed to the "Green Revolution" in rice varieties and their wild progenitors, has also demonstrated sequence diversity, which is correlated with taxonomic classification. These results indicate that detailed analysis of sequence diversity and comparison might give us a clue in elucidating mechanism of the evolution of rice genome.

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Organization of telomeric and subtelomeric chromatin in the higher plant Nicotiana tabacum

Cited by 161 publications

References 19 publications

Telomerase activity in plant cells

Telomerase activity in plant cells

Protection of Telomeres 1 Is Required for Telomere Integrity in the Moss Physcomitrella patens

Comparative Analysis of Rice Genome Sequence to Understand the Molecular Basis of Genome Evolution

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