# overview
My lab is currently investigating mechanisms that regulate telomerase activity in plants. We previously showed that the pattern of telomerase expression in plants is remarkably similar to the pattern seen in humans, despite fundamental differences in development between plants and animals. Telomerase is abundantly expressed in reproductive organs but is undetectable in most vegetative organs (Fitzgerald et al., 1996). Additionally, telomerase can be induced in leaves and other vegetative organs by exposure to exogenous auxin.

To isolate genes that regulate telomerase, we screened a large population of activation tagged lines of Arabidopsis thaliana, and found that several lines that ectopically express telomerase in leaves. The first line we characterized over-expressed a gene encoding a small zinc finger transcription factor we designated TELOMERASE ACTIVATOR 1 (Ren et al., 2004). This factor does not bind to the promoter for TERT, which encodes the catalytically active subunit of telomerase. Instead, it binds to and activates transcription of BT2, a gene encoding a component of a ubiquitin ligase (Ren et al., 2007). Our working model is that the BT2 ubiquitin ligase marks a telomerase repressor for destruction, thereby allowing expression of telomerase. Efforts in the lab are currently focused on identifying the presumed telomerase repressor protein and other proteins that interact with BT2.

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2.2 Factors Relating To The Physical Environment

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30 Agricultural, Veterinary And Food Sciences

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3102 Bioinformatics And Computational Biology

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Fluorescent In Situ Hybridization (fish)

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Global Transcription Factor Group E Protein (gte)

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University of Georgia - (Athens, Georgia, United States)

# educationAndTraining[].organization.label
University of Georgia - (Athens, Georgia, United States)

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Association of Former Students College-Level Teaching Distinguished Achievement Award, The

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Development of transcriptomic resources for interrogating the biosynthesis of monoterpene indole alkaloids in medicinal plant species.

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Expression of enzymatically active and correctly targeted strictosidine synthase in transgenic tobacco plants.

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The secreted purple acid phosphatase isozymes AtPAP12 and AtPAP26 play a pivotal role in extracellular phosphate-scavenging by Arabidopsis thaliana

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Isolation and Mapping of Small Cauliflower Mosaic Virus DNA Fragments Active as Promoters in Escherichia coli.

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Molecular biology of camptothecin production

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ISOLATION AND EXPRESSION OF A TRYPTOPHAN DECARBOXYLASE GENE FROM CAMPTOTHECA-ACUMINATA

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Tissue-Specific Expression of the β-Subunit of Tryptophan Synthase in Camptotheca acuminata, an Indole Alkaloid-Producing Plant

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Sustained harvest of camptothecin from the leaves of Camptotheca acuminata.

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TRANSFORMATION OF PLANTS VIA THE SHOOT APEX

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Ty1-copia-retrotransposon behavior in a polyploid cotton.

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Plant telomeres and telomerases. A review.

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Telomeres, telomerase and plant development

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Different modes of de novo telomere formation by plant telomerases.

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Nucleotide sequence and molecular evolution of two tomato genes encoding the small subunit of ribulose-1,5-bisphosphate carboxylase.

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A disarmed binary vector from Agrobacterium tumefaciens functions in Agrobacterium rhizogenes : Frequent co-transformation of two distinct T-DNAs.

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BT2, a BTB protein, mediates multiple responses to nutrients, stresses, and hormones in Arabidopsis.

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POT1-independent single-strand telomeric DNA binding activities in Brassicaceae.

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Expression of a 3-hydroxy-3-methylglutaryl coenzyme A reductase gene from Camptotheca acuminata is differentially regulated by wounding and methyl jasmonate.

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Molecular cytogenetic mapping of a nucleolar organizer region in cotton

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Evolution of interspersed repetitive elements inGossypium (Malvaceae).

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A simplified and efficient vector-primer cDNA cloning system.

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A rapid procedure for the isolation of C0t-1 DNA from plants.

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Nucleotide sequence of a cDNA encoding the vacuolar protein strictosidine synthase from Catharanthus roseus.

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In situ hybridization of biotinylated DNA probes to cotton meiotic chromosomes.

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Candidate Gene Networks for Acylsugar Metabolism and Plant Defense in Wild Tomato Solanum pennellii

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ACCUMULATION AND BIOSYNTHESIS OF CAMPTOTHECIN AND 10-OH-CAMPTOTHECIN IN CAMPTOTHECA-ACUMINATA

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ISOLATION AND LOCATION OF POTENTIAL PROMOTERS OF CAULIFLOWER MOSAIC-VIRUS

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Use of meiotic FISH for identification of a new monosome in Gossypium hirsutum L.

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Purification and characterization of a secreted purple phosphatase from soybean suspension cultures.

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Fluorescent in situ hybridization of a bacterial artificial chromosome.

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Characterization and preliminary mapping of cauliflower mosaic virus transcripts.

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TELOMERASE ACTIVATOR1 induces telomerase activity and potentiates responses to auxin in Arabidopsis.

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Specialized metabolism by trichome-enriched Rubisco and fatty acid synthase components.

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Regulation of telomerase in Arabidopsis by BT2, an apparent target of TELOMERASE ACTIVATOR1.

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Molecular characterization of two anthranilate synthase alpha subunit genes in Camptotheca acuminata.

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A BTB-TAZ protein is required for gene activation by Cauliflower mosaic virus 35S multimerized enhancers.

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Living with genome instability: plant responses to telomere dysfunction.

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American Association for the Advancement of Science (AAAS)

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Secreted purple acid phosphatase from Arabidopsis thaliana

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Telomeres, telomerase, and stability of the plant genome.

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A secreted purple acid phosphatase from Arabidopsis.

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Sites of accumulation of the antitumor alkaloid camptothecin in Camptotheca acuminata.

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Distribution of 5S and 18S-28S rDNA loci in a tetraploid cotton (Gossypium hirsutum L.) and its putative diploid ancestors.

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Segregation of genes transferred to one plant cell from two separate Agrobacterium strains.

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Identification of a homeologous chromosome pair by in situ DNA hybridization to ribosomal RNA loci in meiotic chromosomes of cotton (Gossypium hirsutum).

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Disruption of the telomerase catalytic subunit gene from Arabidopsis inactivates telomerase and leads to a slow loss of telomeric DNA.

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Proceedings of the National Academy of Sciences

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Characterization and developmental patterns of telomerase expression in plants

# publications[].publisher
Proceedings of the National Academy of Sciences

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New ribosomal RNA gene locations in Gossypium hirsutum mapped by meiotic FISH.

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Analysis of the G‐overhang structures on plant telomeres: evidence for two distinct telomere architectures

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Bromodomain proteins GTE9 and GTE11 are essential for specific BT2-mediated sugar and ABA responses in Arabidopsis thaliana.

# publications[].label
Distribution of 5S and 18S-28S rDNA loci in a tetraploid cotton (Gossypium hirsutum L.) and its putative diploid ancestors

# researcherOn[].label
Genetic Heritability and Spatiotemporal Transcriptional Mapping of the Vocal Learning Process Using A Minimal Song-Training

# researcherOn[].awardedBy.label
National Science Foundation - (Arlington, Virginia, United States)

# streetAddress
Texas A&M University; Biology; 3258 TAMU

# inTheNews[].label
Remembering Longtime Academic Advisor And Texas Graduate Clint Crampton '99