Telomerase-Dependent 3′ G-Strand Overhang Maintenance Facilitates GTBP1-Mediated Telomere Protection from Misplaced Homologous Recombination

Lee, Yong Woo; Kim, Woo Taek

doi:10.1105/tpc.112.107573

Cited by 12 publications

(9 citation statements)

References 55 publications

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“…In contrast, sorghum, rice, and maize show non-Rabl patterns. In the case of tobacco, the telomeres are localized at random in the nucleus in a typical non-Rabl pattern (Fujimoto et al 2005, Lee and Kim 2013, Schrumpfová et al 2014. The signal pattern observed with dCas9-FP for telomeres was similar to previous telomere localization patterns in tobacco.…”

Section: Transient Expression Of Dcas9-fp and Sgrna For Telomeres In supporting

confidence: 84%

Visualization of Chromatin Loci with Transiently Expressed CRISPR/Cas9 in Plants

Fujimoto

Matsunaga

2017

CYTOLOGIA

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Labeling of specific DNA sequences in living organisms is important for understanding the mechanism of gene regulation during development, differentiation, and environmental adaptation. Here we describe a CRISPR/Cas9-based chromatin visualization system in plants. We adapted the mammalian nuclease-dead Cas9fluorescent protein (dCas9-FP) system to a plant expression vector. Transient expression of dCas9-FP and single guide RNA (sgRNA) for telomeric sequences efficiently labeled telomere repeats in tobacco.

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Section: Transient Expression Of Dcas9-fp and Sgrna For Telomeres In supporting

confidence: 84%

Visualization of Chromatin Loci with Transiently Expressed CRISPR/Cas9 in Plants

Fujimoto

Matsunaga

2017

CYTOLOGIA

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“…Furthermore, two‐dimensional (2‐D) pulse‐field gel electrophoresis assays detected no generation of extra‐chromosomal telomeric circles (t‐circles) in both wild type and osrad51d mutant plants (Figure S5). t‐circles result from abnormal inter‐telomeric HR (Zellinger et al ., ; Lee and Kim, , ). osku70 mutant rice exhibit developmental defects in both vegetative and reproductive organs with numerous abnormal anaphase telomeric bridges (Hong et al ., ).…”

Section: Resultsmentioning

confidence: 99%

Suppression of OsRAD51D results in defects in reproductive development in rice (Oryza sativa L.)

Byun

Kim

2014

The Plant Journal

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SUMMARYThe cellular roles of RAD51 paralogs in somatic and reproductive growth have been extensively described in a wide range of animal systems and, to a lesser extent, in Arabidopsis, a dicot model plant. Here, the Os-RAD51D gene was identified and characterized in rice (Oryza sativa L.), a monocot model crop. In the rice genome, three alternative OsRAD51D mRNA splicing variants, OsRAD51D.1, OsRAD51D.2, and OsRAD51D.3, were predicted. Yeast two-hybrid studies, however, showed that only OsRAD51D.1 interacted with Os-RAD51B and OsRAD51C paralogs, suggesting that OsRAD51D.1 is a functional OsRAD51D protein in rice. Loss-of-function osrad51d mutant rice plants displayed normal vegetative growth. However, the mutant plants were defective in reproductive growth, resulting in sterile flowers. Homozygous osrad51d mutant flowers exhibited impaired development of lemma and palea and contained unusual numbers of stamens and stigmas. During early meiosis, osrad51d pollen mother cells (PMCs) failed to form normal homologous chromosome pairings. In subsequent meiotic progression, mutant PMCs represented fragmented chromosomes. The osrad51d pollen cells contained numerous abnormal micro-nuclei that resulted in malfunctioning pollen. The abnormalities of heterozygous mutant and T2 Ubi:RNAi-OsRAD51D RNAi-knock-down transgenic plants were intermediate between those of wild type and homozygous mutant plants. The osrad51d and Ubi:RNAi-OsRAD51D plants contained longer telomeres compared with wild type plants, indicating that OsRAD51D is a negative factor for telomere lengthening. Overall, these results suggest that OsRAD51D plays a critical role in reproductive growth in rice. This essential function of OsRAD51D is distinct from Arabidopsis, in which AtRAD51D is not an essential factor for meiosis or reproductive development.

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“…In addition to the telomerase-mediated telomere elongation, multiple other processes can influence telomere G-overhang length and the terminal sequences 3 . Therefore, telomerase activity is necessary for the normal length of telomere G-overhang in certain eukaryotic organisms 33 , 34 but not others 35 – 37 . Interestingly, we found that T .…”

Section: Discussionmentioning

confidence: 99%

“…Indeed, expression of telomerase results in longer G-overhangs at the leading daughter telomeres in human cells 32 while dysfunctional telomerase leads to shorter telomere G-overhangs in tobacco and S . castellii 33 , 34 . However, telomerase deletion does not affect telomere G-overhang length in S .…”

Section: Introductionmentioning

confidence: 99%

Telomerase activity is required for the telomere G-overhang structure in Trypanosoma brucei

Sandhu

2017

Sci Rep

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Trypanosoma brucei causes fatal human African trypanosomiasis and evades the host immune response by regularly switching its major surface antigen, VSG, which is expressed exclusively from subtelomeric loci. Telomere length and telomere proteins play important roles in regulating VSG silencing and switching. T. brucei telomerase plays a key role in maintaining telomere length, and T. brucei telomeres terminate in a single-stranded 3′ G-rich overhang. Understanding the detailed structure of the telomere G-overhang and its maintenance will contribute greatly to better understanding telomere maintenance mechanisms. Using an optimized adaptor ligation assay, we found that most T. brucei telomere G-overhangs end in 5′ TTAGGG 3′, while a small portion of G-overhangs end in 5′ TAGGGT 3′. Additionally, the protein and the RNA components of the telomerase (TbTERT and TbTR) and TbKu are required for telomere G-overhangs that end in 5′ TTAGGG 3′ but do not significantly affect the 5′ TAGGGT 3′-ending overhangs, indicating that telomerase-mediated telomere synthesis is important for the telomere G-overhang structure. Furthermore, using telomere oligo ligation-mediated PCR, we showed for the first time that the T. brucei telomere 5′ end sequence – an important feature of the telomere terminal structure – is not random but preferentially 5′ CCTAAC 3′.

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Telomerase-Dependent 3′ G-Strand Overhang Maintenance Facilitates GTBP1-Mediated Telomere Protection from Misplaced Homologous Recombination

Cited by 12 publications

References 55 publications

Visualization of Chromatin Loci with Transiently Expressed CRISPR/Cas9 in Plants

Visualization of Chromatin Loci with Transiently Expressed CRISPR/Cas9 in Plants

Suppression of OsRAD51D results in defects in reproductive development in rice (Oryza sativa L.)

Telomerase activity is required for the telomere G-overhang structure in Trypanosoma brucei

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