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Malligarjunan Rajavel, Tivadar Orban, Mengyuan Xu, Wilnelly Hernandez-Sanchez, Maria de la Fuente, Krzysztof Palczewski, Derek J Taylor
Telomeres are specialized nucleoprotein complexes that comprise the ends of linear chromosomes. Human telomeres end in a short, single-stranded DNA (ssDNA) overhang that is recognized and bound by two telomere proteins, POT1 and TPP1. Whereas POT1 binds directly to telomere ssDNA, its interaction with TPP1 is essential for localization of POT1 to the telomere. TPP1 also provides enhanced binding and sequence discrimination that regulates POT1-TPP1 interactions exclusively with telomere ssDNA. Finally, TPP1 recruits telomerase, the enzyme responsible for synthesis of telomere DNA, to the telomere...
September 20, 2016: Nucleic Acids Research
Caroline Lebaron, Aurélie Rosado, Christopher Sauvage, Camille Gauffier, Sylvie German-Retana, Benoît Moury, Jean-Luc Gallois
Allele mining on susceptibility factors offers opportunities to find new sources of resistance among crop wild relatives for breeding purposes. As a proof of concept, we used available RNAseq data to investigate polymorphisms among the four tomato genes encoding translation initiation factors (eIF4E1 and eIF4E2, eIFiso4E and the related gene New Cap-binding Protein -nCBP) to look for new potential resistance alleles to potyviruses. By analyzing polymorphism among RNAseq data obtained for 20 tomato accessions, ten belonging to the cultivated type Solanum lycopersicum and 10 belonging to the closest related wild species Solanum pimpinellifolium, we isolated one new eIF4E1 allele, in the Solanum pimpinellifolium LA0411 accession, which encodes a potential new resistance allele, mainly due to a polymorphism associated with an amino acid change within eIF4E1 region II...
September 19, 2016: Journal of General Virology
Shanshan Yin, Yan Huang, Yingnan Zhangfang, Xiaoqin Zhong, Pengqing Li, Junjiu Huang, Dan Liu, Zhou Songyang
The planarian flatworm is an emerging model that is useful for studying homeostasis and regeneration due to its unique adult stem cells (ASCs). Previously, planaria were found to share mammalian TTAGGG chromosome ends and telomerases; however, their telomere protection proteins have not yet been identified. In Schmidtea mediterranea, we identified a homologue of the human protection of telomeres 1 (POT1) with an OB-fold (SmedOB1). SmedOB1 is evolutionarily conserved among species and is ubiquitously expressed throughout the whole body...
2016: Scientific Reports
Amit Arora, Mark A Beilstein, Dorothy E Shippen
Protection of telomeres (POT1) binds chromosome ends, recognizing single-strand telomeric DNA via two oligonucleotide/oligosaccharide binding folds (OB-folds). The Arabidopsis thaliana POT1a and POT1b paralogs are atypical: they do not exhibit telomeric DNA binding, and they have opposing roles in regulating telomerase activity. AtPOT1a stimulates repeat addition processivity of the canonical telomerase enzyme, while AtPOT1b interacts with a regulatory lncRNA that represses telomerase activity. Here, we show that OB1 of POT1a, but not POT1b, has an intrinsic affinity for telomeric DNA...
September 19, 2016: Nucleic Acids Research
Neil R Lloyd, Thayne H Dickey, Robert A Hom, Deborah S Wuttke
Telomeres terminate nearly exclusively in single-stranded DNA (ssDNA) overhangs comprised of the G-rich 3' end. This overhang varies widely in length from species to species, ranging from just a few bases to several hundred nucleotides. These overhangs are not merely a remnant of DNA replication but rather are the result of complex further processing. Proper management of the telomeric overhang is required both to deter the action of the DNA damage machinery and to present the ends properly to the replicative enzyme telomerase...
September 27, 2016: Biochemistry
Helen E Speedy, Ben Kinnersley, Daniel Chubb, Peter Broderick, Philip J Law, Kevin Litchfield, Sandrine Jayne, Martin J S Dyer, Claire Dearden, George A Follows, Daniel Catovsky, Richard S Houlston
Chronic lymphocytic leukemia (CLL) can be familial, however thus far no rare germline disruptive alleles for CLL have been identified. We performed whole-exome sequencing of 66 CLL families, identifying four families where loss-of-function mutations in POT1 co-segregated with CLL. The p.Tyr36Cys mutation is predicted to disrupt the interaction between POT1 and the telomeric overhang. The c.1164-1G>A splice-site, p.Gln358SerfsTer13 frameshift and p.Gln376Arg missense mutations are likely to impact the interaction between POT1 and ACD, part of the telomere-capping shelterin complex...
August 15, 2016: Blood
Ilgen Mender, Jerry W Shay
Telomerase maintains telomeric DNA in eukaryotes during early developments, ~90% of cancer cells and some proliferative stem like cells. Telomeric repeats at the end of chromosomes are associated with the shelterin complex. This complex consists of TRF1, TRF2, Rap1, TIN2, TPP1, POT1 which protect DNA from being recognized as DNA double-stranded breaks. Critically short telomeres or impaired shelterin proteins can cause telomere dysfunction, which eventually induces DNA damage responses at the telomeres. DNA damage responses can be identified by antibodies to 53BP1, gammaH2AX, Rad17, ATM, and Mre11...
November 20, 2015: Bio-protocol
Romain Guièze, Mélanie Pages, Lauren Véronèse, Patricia Combes, Richard Lemal, Mathilde Gay-Bellile, Martine Chauvet, Mary Callanan, Fabrice Kwiatkowski, Bruno Pereira, Philippe Vago, Jacques-Olivier Bay, Olivier Tournilhac, Andreï Tchirkov
In chronic lymphocytic leukemia (CLL), telomere dysfunction is associated with poor outcomes. TP53 is involved in cellular responses to dysfunctional telomeres, and its inactivation is the strongest adverse prognostic factor for CLL. Given the biological relationship between TP53 and telomeres, and their prognostic value, it is important to improve our understanding of the impact of TP53 alterations on telomeres. We performed a comprehensive study of the deletions and mutations of the TP53 gene and telomere parameters, including hTERT and the shelterin complex, in 115 CLL patients...
July 29, 2016: Oncotarget
Lihua Yao, Xiaolan Guo
As an important telomere binding protein, TPP1 protects the ends of telomeres and maintains the stability and integrity of its structure and function by interacting with other five essential core proteins (POT1, TRF1, TRF2, TIN2, and RAP1) to form a complex called Shelterin. Recently, researchers have discovered that TPP1 participates in protection of telomeres and regulation of telomerase activity. The relationship between TPP1 and tumorigenesis, tumor progression and treatment has also been investigated. This paper reviews the latest findings of TPP1 regarding to its structure, function and interaction with other proteins involved in tumorigenesis...
August 2016: Zhonghua Yi Xue Yi Chuan Xue za Zhi, Zhonghua Yixue Yichuanxue Zazhi, Chinese Journal of Medical Genetics
Umesh Kalathiya, Monikaben Padariya, Maciej Baginski
Shelterin is a six-protein complex (TRF1, TRF2, POT1, RAP1, TIN2, and TPP1) that also functions in smaller subsets in regulation and protection of human telomeres. Two closely related proteins, TRF1 and TRF2, make high-affinity contact directly with double-stranded telomeric DNA and serve as a molecular platform. Protein TIN2 binds to TRF1 and TRF2 dimer-forming domains, whereas Apollo makes interaction only with TRF2. To elucidate the molecular basis of these interactions, we employed molecular dynamics (MD) simulations of TRF1TRFH-TIN2TBM and TRF2TRFH-TIN2TBM/ApolloTBM complexes and of the isolated proteins...
July 22, 2016: European Biophysics Journal: EBJ
Agnel Sfeir, Eros Lazzerini Denchi
No abstract text is available yet for this article.
July 13, 2016: Oncotarget
Yugo Hirai, Miki Tamura, Junji Otani, Fuyuki Ishikawa
Shelterin component TPP1 plays critical roles in chromosome end protection and telomere length regulation. Specifically, TPP1 contains an OB-fold domain that provides an interface to recruit telomerase. However, it remains largely unknown how telomerase recruitment is regulated by cell cycle regulators. We show that TPP1 interacts with the cell cycle regulator kinase NEK6 in human cells. We found that NEK6-mediated phosphorylation of TPP1 Ser255 in G2/M phase regulates the association between telomerase activity and TPP1...
August 2016: Genes to Cells: Devoted to Molecular & Cellular Mechanisms
Daniel Chubb, Peter Broderick, Sara E Dobbins, Matthew Frampton, Ben Kinnersley, Steven Penegar, Amy Price, Yussanne P Ma, Amy L Sherborne, Claire Palles, Maria N Timofeeva, D Timothy Bishop, Malcolm G Dunlop, Ian Tomlinson, Richard S Houlston
Colorectal cancer (CRC) displays a complex pattern of inheritance. It is postulated that much of the missing heritability of CRC is enshrined in high-impact rare alleles, which are mechanistically and clinically important. In this study, we assay the impact of rare germline mutations on CRC, analysing high-coverage exome sequencing data on 1,006 early-onset familial CRC cases and 1,609 healthy controls, with additional sequencing and array data on up to 5,552 cases and 6,792 controls. We identify highly penetrant rare mutations in 16% of familial CRC...
June 22, 2016: Nature Communications
Tuanwei Wang, Sihua Wang, Xiaoran Duan, Xiaolei Feng, Pengpeng Wang, Wu Yao, Yongjun Wu, Feifei Feng, Songcheng Yu, Yiming Wu, Wei Wang
Protection of telomeres protein 1 (POT1) plays pivotal roles in protection of chromosome ends and regulation of telomere length with other telomere binding proteins; its genetic polymorphisms are associated with many diseases. In this study, we explored a novel PCR-RFLP method for typing the single nucleotide polymorphism (SNP) rs1034794 of the human POT1 gene. A new restriction enzyme site was introduced into a POT1 gene amplification product by created restriction site PCR (CRS-PCR). One primer was designed based on changed sequence; after PCR amplification, a new restriction enzyme site for AluI was introduced into the PCR products...
June 2016: Biochemistry. Biokhimii︠a︡
Huazong Yin, Liuwang Nie, Feifei Zhao, Huaxing Zhou, Haifeng Li, Xianmei Dong, Huanhuan Zhang, Yuqin Wang, Qiong Shi, Jun Li
Mauremys reevesii (Geoemydidae) is one of the most common and widespread semi-aquatic turtles in East Asia. The unusually long lifespan of some individuals makes this turtle species a potentially useful model organism for studying the molecular basis of longevity. In this study, pooled total RNA extracted from liver, spleen and skeletal-muscle of three adult individuals were sequenced using Illumina Hiseq 2500 platform. A set of telomere-related genes were found in the transcriptome, including tert, tep1, and six shelterin complex proteins coding genes (trf1, trf2, tpp1, pot1, tin2 and rap1)...
2016: PeerJ
Sihua Wang, Xiaoran Duan, Tuanwei Wang, Xiaolei Feng, Pengpeng Wang, Wu Yao, Yongjun Wu, Yiming Wu, Zhen Yan, Feifei Feng, Songcheng Yu, Wei Wang
Human protection of telomeres 1 (POT1) gene is a single stranded telomere binding proteins with a critical role in ensuring chromosome stability. There have been variants of POT1 gene, and the polymorphisms of POT1 gene were associated with some diseases. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) is a traditional method to detect the single nucleotide polymorphism (SNP), and it can be used to detect the polymorphism of rs10250202. But the restriction enzymes required for the detection of the polymorphism of rs10250202 are expensive...
2016: SpringerPlus
Cory Rice, Emmanuel Skordalakes
Telomeres comprise the ends of eukaryotic chromosomes and are essential for cell proliferation and genome maintenance. Telomeres are replicated by telomerase, a ribonucleoprotein (RNP) reverse transcriptase, and are maintained primarily by nucleoprotein complexes such as shelterin (TRF1, TRF2, TIN2, RAP1, POT1, TPP1) and CST (Cdc13/Ctc1, Stn1, Ten1). The focus of this review is on the CST complex and its role in telomere maintenance. Although initially thought to be unique to yeast, it is now evident that the CST complex is present in a diverse range of organisms where it contributes to genome maintenance...
2016: Computational and Structural Biotechnology Journal
Alexandra M Pinzaru, Robert A Hom, Angela Beal, Aaron F Phillips, Eric Ni, Timothy Cardozo, Nidhi Nair, Jaehyuk Choi, Deborah S Wuttke, Agnel Sfeir, Eros Lazzerini Denchi
Genome sequencing studies have revealed a number of cancer-associated mutations in the telomere-binding factor POT1. Here, we show that when combined with p53 deficiency, depletion of murine POT1a in common lymphoid progenitor cells fosters genetic instability, accelerates the onset, and increases the severity of T cell lymphomas. In parallel, we examined human and mouse cells carrying POT1 mutations found in cutaneous T cell lymphoma (CTCL) patients. Inhibition of POT1 activates ATR-dependent DNA damage signaling and induces telomere fragility, replication fork stalling, and telomere elongation...
June 7, 2016: Cell Reports
Chia-Hsin Su, Ching Cheng, Tsai-Yu Tzeng, I-Hsuan Lin, Ming-Ta Hsu
Telomeres are capped at the ends of eukaryotic chromosomes and are composed of TTAGGG repeats bound to the shelterin complex. Here we report that a replication-dependent histone H2A isotype, H2ac, was associated with telomeres in human cells and co-immunoprecipitates with telomere repeat factor 2 (TRF2) and protection of telomeres protein 1 (POT1), whereas other histone H2A isotypes and mutations of H2ac did not bind to telomeres or these two proteins. The amino terminal basic domain of TRF2 was necessary for the association with H2ac and for the recruitment of H2ac to telomeres...
2016: PloS One
Carmen Diana Herling, Marion Klaumünzer, Cristiano Krings Rocha, Janine Altmüller, Holger Thiele, Jasmin Bahlo, Sandra Kluth, Giuliano Crispatzu, Marco Herling, Joanna Schiller, Anja Engelke, Eugen Tausch, Hartmut Döhner, Kirsten Fischer, Valentin Goede, Peter Nürnberg, Hans Christian Reinhardt, Stephan Stilgenbauer, Michael Hallek, Karl-Anton Kreuzer
Genetic instability is a feature of chronic lymphocytic leukemia (CLL) with adverse prognosis. We hypothesized that chromosomal translocations or complex karyotypes and distinct somatic mutations may impact outcome after first-line chemoimmunotherapy of CLL patients. We performed metaphase karyotyping and next-generation sequencing (NGS) of 85 genes in pretreatment blood samples obtained from 161 patients registered for CLL11, a 3-arm phase 3 trial comparing frontline chlorambucil (Clb) vs Clb plus rituximab (Clb-R) or Clb plus obinutuzumab in CLL patients with significant comorbidity...
July 21, 2016: Blood
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