A5033979709- Telomeres, Telomerase, and Senescence
- Chromosomal and Genetic Variations
- CRISPR and Genetic Engineering
- DNA Repair Mechanisms
- Plant Molecular Biology Research
- Silicon Effects in Agriculture
- Polar Research and Ecology
- RNA modifications and cancer
- Genetics, Aging, and Longevity in Model Organisms
- Advanced biosensing and bioanalysis techniques
- Genomics and Phylogenetic Studies
- Cancer-related molecular mechanisms research
- Plant Genetic and Mutation Studies
- Animal Genetics and Reproduction
- Microplastics and Plastic Pollution
- Protist diversity and phylogeny
- RNA Interference and Gene Delivery
- Cancer Research and Treatments
- Plant Diversity and Evolution
- Mitochondrial Function and Pathology
- Photosynthetic Processes and Mechanisms
- Epigenetics and DNA Methylation
- Plant Reproductive Biology
- Virus-based gene therapy research
- Parasitic Infections and Diagnostics
Texas A&M University
2015-2024
Mitchell Institute
2003-2024
Ohio University
2024
National Postdoctoral Association
2024
Kazan Federal University
2023
Marshall University
2023
The University of Texas at Austin
2023
University of Colorado Boulder
2010
Baylor College of Medicine
2010
University of California, San Francisco
1994-2008
In the early 1990s an outbreak of papaya ringspot virus (PRSV) in groves Puna district Hawaii caused severe damage to important crop. Since then, planting two transgenic cultivars resistant — called 'SunUp' and 'Rainbow' has helped maintain yields. SunUp is a red-fleshed fruit that expresses coat protein gene mild mutant PRSV, conferring resistance via post-transcriptional silencing. Rainbow yellow-fleshed (and therefore more popular) F1 hybrid bred from SunUp. Now draft genome sequence...
Vascular plants appeared ~410 million years ago, then diverged into several lineages of which only two survive: the euphyllophytes (ferns and seed plants) lycophytes. We report here genome sequence lycophyte Selaginella moellendorffii (Selaginella), first nonseed vascular plant reported. By comparing gene content in evolutionarily diverse taxa, we found that transition from a gametophyte- to sporophyte-dominated life cycle required far fewer new genes than flowering plant, whereas secondary...
Genome packaging by nucleosomes is a hallmark of eukaryotes. Histones and the pathways that deposit, remove, read histone modifications are deeply conserved. Yet, we lack information regarding chromatin landscapes in extant representatives ancestors main groups eukaryotes, our knowledge evolution chromatin-related processes limited. We used bryophyte Marchantia polymorpha, which diverged from vascular plants circa 400 mya, to obtain whole chromosome genome assembly explore landscape...
Loss of telomere function in metazoans results catastrophic damage to the genome, cell cycle arrest, and apoptosis. Here we show that mustard weed Arabidopsis thaliana can survive up 10 generations without telomerase. The last five telomerase-deficient plants endured increasing levels cytogenetic damage, which was correlated with developmental anomalies both vegetative reproductive organs. Mutants ultimately arrested at a terminal state harboring shoot meristems were grossly enlarged,...
Telomerase is an essential enzyme that maintains telomeres on eukaryotic chromosomes. In mammals, telomerase required for the lifelong proliferative capacity of normal regenerative and reproductive tissues sustained growth in a dedifferentiated state. Although importance was first elucidated plants 60 years ago, little known about role plant development. Here we report cloning characterization Arabidopsis reverse transcriptase (TERT) gene, AtTERT. AtTERT predicted to encode highly basic...
Telomerase activity is developmentally regulated in mammals. Here we examine telomerase plants, whose development differs fundamental ways from that of animals. Using a modified version the telomere repeat amplification protocol (TRAP) assay, detected an extracts carrots, cauliflower, soybean, Arabidopsis , and rice with all characteristics expected for synthesizing plant sequence TTTAGGG. The was dependent on RNA protein components, required dGTP, dATP, dTTP, but not dCTP, generated...
Pot1 (protection of telomeres 1) is a single-stranded telomere binding protein that essential for chromosome end protection and length homeostasis. Arabidopsis encodes two Pot1-like proteins, dubbed AtPot1 AtPot2. Here we show in transgenic plants expressing truncated allele lacking the N-terminal oligonucleotide/oligosaccharide fold (P1ΔN) are 1 to 1.5 kb shorter than wild type, suggesting contributes positive regulation control. In contrast, unperturbed analogous region A strikingly...
Abstract Telomeres are highly repetitive DNA sequences found at the ends of chromosomes that protect from deterioration duringcell division. Here, using whole-genome re-sequencing and terminal restriction fragment assays, we substantial natural intraspecific variation in telomere length Arabidopsis thaliana, rice (Oryza sativa), maize (Zea mays). Genome-wide association study (GWAS) mapping A. thaliana identified 13 regions with GWAS-significant associations underlying variation, including a...
Although length of the telomeric DNA tract varies widely across evolution, a species-specific set point is established and maintained by unknown mechanisms. To investigate how telomere controlled in Arabidopsis thaliana, we analyzed bulk 14 wild-type accessions. We found that tracts are fairly uniformly distributed throughout size range 2 to 9 kb. Unexpectedly, telomeres plants Wassilewskija ecotype displayed bimodal distribution, with some individuals harboring 5 kb others 4 F1 F2 progeny...
Telomere dysfunction arising from mutations in telomerase or telomere capping proteins leads to end-to-end chromosome fusions. Paradoxically, the Ku70/80 heterodimer, essential for nonhomologous end-joining double-strand break repair, is also found at telomeres, and mammals it required prevent fusion. Previously, we showed that inactivation of Ku70 Arabidopsis results lengthening. Here, have demonstrated this elongation dependent. Further, terminal 3′ G overhang was significantly extended...
Telomeres shield the natural ends of chromosomes from nucleolytic attack, recognition as double-strand breaks, and inappropriate processing by DNA repair machinery. The trimeric Stn1/Ten1/Cdc13 complex is critical for chromosome end protection in Saccharomyces cerevisiae , while vertebrate telomeres are protected shelterin, a six proteins that does not include STN1 or TEN1. Recent studies demonstrate Stn1 Ten1 orthologs Schizosaccharomyces pombe contribute to telomere integrity distinct...
Meiosis consists of two nuclear divisions that are separated by a short interkinesis. Here we show the SMG7 protein, which plays an evolutionarily conserved role in nonsense-mediated RNA decay (NMD) animals and yeast, is essential for progression from anaphase to telophase second meiotic division Arabidopsis. Arabidopsis gene, disruption causes embryonic lethality. Plants carrying hypomorphic smg7 mutation exhibit elevated level transcripts containing premature stop codons. This suggests NMD...
Dyskerin binds the H/ACA box of human telomerase RNA and is a core subunit required for RNP biogenesis enzyme function in vivo. Missense mutations dyskerin result dyskeratosis congenita, complex syndrome characterized by bone marrow failure, deficiency, progressive telomere shortening. Here we demonstrate that also contributes to maintenance Arabidopsis thaliana. We report both AtNAP57, homolog, AtTERT, catalytic subunit, accumulate plant nucleolus, AtNAP57 associates with active particles...
Telomerase is a ribonucleoprotein (RNP) reverse transcriptase whose essential RNA subunit (TER) functions as template for telomere repeat synthesis. Here we report the identification of two divergent TER moieties in flowering plant Arabidopsis thaliana. Although both TER1 and TER2 copurify with telomerase activity serve templates vitro, depletion TER1, but not TER2, leads to decreased progressive shortening vivo. Moreover, mutation templating domain results incorporation mutant repeats on...
Abstract Telomere maintenance is a fundamental cellular process conserved across all eukaryotic lineages. Although plants and animals diverged over 1.5 billion years ago, lessons learned from continue to push the boundaries of science, revealing detailed molecular mechanisms in telomere biology with broad implications for human health, aging biology, stress responses. Recent studies plant telomeres have unveiled unexpected divergence sequence architecture, proteins that engage telomeric DNA...
Little is known about the protein composition of plant telomeres. We queried Arabidopsis thaliana genome data base in search genes with similarity to human telomere proteins hTRF1 and hTRF2. hTRF1/hTRF2 are distinguished by presence a single Myb-like domain their C terminus that required for telomeric DNA binding vitro. Twelve fitting this criterion, dubbed TRF-like (TRFL), fell into two distinct gene families. Notably, TRFL family 1 possessed highly conserved region C-terminal Myb called...
In the absence of telomerase, telomeres undergo progressive shortening and are ultimately recruited into end-to-end chromosome fusions via non-homologous end joining (NHEJ) double-strand break repair pathway. Previously, we showed that fusion critically shortened in Arabidopsis proceeds with approximately same efficiency presence or KU70, a key component NHEJ. Here report DNA ligase IV (LIG4) is also not essential for telomere joining. We observed only modest decrease (3-fold) frequency...
Abstract Conversion of a double-strand break into telomere is dangerous, potentially lethal event. However, little known about the mechanism and control de novo formation (DNTF). DNTF can be instigated by insertion repeat array (TRA) host genome, which seeds new telomere, resulting in chromosome truncation. Such events are rare concentrated at ends. Here, we introduce tetraploid Arabidopsis thaliana as robust genetic model for DNTF. Transformation 2.6-kb TRA plants resulted efficiency 56%,...