Minisatellite telomeres occur in the family Alliaceae but are lost in <i>Allium</i>

Sýkorová, Eva; Fajkus, Jiřı́; Mezníková, Marie; Lim, K. Yoong; Neplechová, Kamila; Blattner, Frank R.; Chase, Mark W.; Leitch, Andrew R.

doi:10.3732/ajb.93.6.814

Cited by 58 publications

(58 citation statements)

References 41 publications

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“…For example, the polymorphic minisatellite in the promoter region of the human insulin gene alters transcription according to minisatellite size (Kennedy et al, 1995). In plants, although minisatellites have been used for various evolutionary studies (Sykorova et al, 2006), fingerprinting (Nybom et al, 1990;Tzuri et al, 1991), and mapping (Barreneche et al, 1998), there is little evidence to date of minisatellite-induced changes to transcriptional regulation.…”

Section: A Minisatellite Alters the Promoter Of Myb10 In Red-fleshed mentioning

confidence: 99%

Multiple Repeats of a Promoter Segment Causes Transcription Factor Autoregulation in Red Apples

et al. 2009

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Mutations in the genes encoding for either the biosynthetic or transcriptional regulation of the anthocyanin pathway have been linked to color phenotypes. Generally, this is a loss of function resulting in a reduction or a change in the distribution of anthocyanin. Here, we describe a rearrangement in the upstream regulatory region of the gene encoding an apple (Malus 3 domestica) anthocyanin-regulating transcription factor, MYB10. We show that this modification is responsible for increasing the level of anthocyanin throughout the plant to produce a striking phenotype that includes red foliage and red fruit flesh. This rearrangement is a series of multiple repeats, forming a minisatellite-like structure that comprises five direct tandem repeats of a 23-bp sequence. This MYB10 rearrangement is present in all the red foliage apple varieties and species tested but in none of the white fleshed varieties. Transient assays demonstrated that the 23-bp sequence motif is a target of the MYB10 protein itself, and the number of repeat units correlates with an increase in transactivation by MYB10 protein. We show that the repeat motif is capable of binding MYB10 protein in electrophoretic mobility shift assays. Taken together, these results indicate that an allelic rearrangement in the promoter of MYB10 has generated an autoregulatory locus, and this autoregulation is sufficient to account for the increase in MYB10 transcript levels and subsequent ectopic accumulation of anthocyanins throughout the plant.

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Section: A Minisatellite Alters the Promoter Of Myb10 In Red-fleshed mentioning

confidence: 99%

Multiple Repeats of a Promoter Segment Causes Transcription Factor Autoregulation in Red Apples

et al. 2009

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“…Species of Allium were shown to be the exception even to this with no recognisable minisatellite so far identified [50].…”

Section: Chromosome Packaging and Organizationmentioning

confidence: 99%

Genome Size Dynamics and Evolution in Monocots

et al. 2010

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Monocot genomic diversity includes striking variation at many levels. This paper compares various genomic characters (e.g., range of chromosome numbers and ploidy levels, occurrence of endopolyploidy, GC content, chromosome packaging and organization, genome size) between monocots and the remaining angiosperms to discern just how distinctive monocot genomes are. One of the most notable features of monocots is their wide range and diversity of genome sizes, including the species with the largest genome so far reported in plants. This genomic character is analysed in greater detail, within a phylogenetic context. By surveying available genome size and chromosome data it is apparent that different monocot orders follow distinctive modes of genome size and chromosome evolution. Further insights into genome size-evolution and dynamics were obtained using statistical modelling approaches to reconstruct the ancestral genome size at key nodes across the monocot phylogenetic tree. Such approaches reveal that while the ancestral genome size of all monocots was small (1C = 1.9 pg), there have been several major increases and decreases during monocot evolution. In addition, notable increases in the rates of genome size-evolution were found in Asparagales and Poales compared with other monocot lineages.

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“…The del11 variant was most abundant in telomerase-negative tissues (leaf) and accompanied the full-length variant in telomerasepositive tissues [immature embryo, cell suspension, callus (Heller-Uszynska et al, 2002)]. Other data came from the order Asparagales, a group of plants of interest because their telomerases switched synthesis from the Arabidopsis-like (TTTAGGG) to the human-like (TTAGGG) telomere motif (Sykorova et al, 2003(Sykorova et al, , 2006a(Sykorova et al, , 2006b). In the case of Iris telomerase, a number of alternatively spliced transcripts were cloned in an attempt to obtain fulllength cDNA using primer sites from the start to stop codon.…”

Section: Alternative Splicing Variants Of Plant Tertsmentioning

confidence: 99%

“…The variants leading to in-frame transcripts are underlined; variants without a defined ORF are in brackets. Sykorova et al (2006b) includes approx. 37 kb of genomic DNA, 33 kb of which constitute intronic sequences and the remaining approx.…”

Section: Alternative Splicing Variants Of Vertebrate Tertsmentioning

confidence: 99%

Structure—function relationships in telomerase genes

Sýkorová

Fajkus

2009

Biology of the Cell

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The TERT (telomerase reverse transcriptase) subunit of telomerase is an intensively studied macromolecule due to its key importance in maintaining genome integrity and role in cellular aging and cancer. In an effort to provide an up-to-date overview of the topic, we discuss the structure of TERT genes, their alternative splicing products and their functions. Nucleotide databases contain more than 90 full-length cDNA sequences of telomerase protein subunits. Numerous in silico, in vitro and in vivo experimental techniques have revealed a great deal of structural and functional data describing particular features of the telomerase subunit in various model organisms. We explore whether particular findings are generally applicable to telomerases or species-specific. We also discuss in an evolutionary context the role of identified functional TERT subdomains. IntroductionTelomeres are nucleoprotein structures at the ends of eukaryotic chromosomes which protect linear chromosomes against damage and recognition by endogenous nucleases. The vital role of these structures has been demonstrated in observations of a breakage-fusion-bridge cycle by Barbara McClintock (1938) in plants and response to X-ray mediated damage by Hermann Muller (1938) in Drosophila. With understanding of the mechanism of DNA replication, the "end-replication problem" of linear chromosomes became apparent (Olovnikov, 1971; Watson, 1972;Olovnikov, 1973). However, fundamental features of telomere structure and protective function were not solved until later when the ends of Tetrahymena macronuclear minichromosomes were sequenced (Klobutcher et al., 1981) and the activity of telomerase, the enzyme responsible for their synthesis described (Greider and Blackburn, 1985; 1 To whom correspondence should be addressed (email fajkus@sci.muni.cz). Key words: alternative splicing, gene structure, telomerase. Abbreviations used: CTE, C-terminal extension; EST, expressed sequence tag; DAT, dissociate activities of telomerase; Est, ever-shorter telomere; FHC cell, fetal human colon cell; POT1, protection of telomeres protein 1; RT, reverse transcriptase; SWI/SNF, switch/sucrose non-fermentable; TERT, telomerase reverse transcriptase; AtTERT, Arabidopsis thaliana TERT; hTERT, human TERT; OsTERT, rice (Oryza sativa) TERT; TR, telomerase RNA; TRF2, telomere repeat factor 2. Greider and Blackburn, 1987). It is known now that telomere structure is formed by telomeric DNA, histone octamers and specific proteins that bind telomeric DNA either directly or indirectly by proteinprotein interactions (Fajkus and Trifonov, 2001; de Lange, 2005; Bianchi and Shore, 2008;Palm and de Lange, 2008) (Figure 1). The number of components of the telomere supramolecular structure, and knowledge of their roles in protecting and maintaining telomeres, have increased enormously within the last 15 years. Clearly telomerase is among the most important molecules in the field of telomere biology and is the subject of this review. General telomerase biologyTelomerase adds telomeric DNA re...

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Minisatellite telomeres occur in the family Alliaceae but are lost in Allium

Cited by 58 publications

References 41 publications

Multiple Repeats of a Promoter Segment Causes Transcription Factor Autoregulation in Red Apples

Multiple Repeats of a Promoter Segment Causes Transcription Factor Autoregulation in Red Apples

Genome Size Dynamics and Evolution in Monocots

Structure—function relationships in telomerase genes

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