A5073887433- Protist diversity and phylogeny
- Microtubule and mitosis dynamics
- Genetic and Kidney Cyst Diseases
- Ubiquitin and proteasome pathways
- Microbial Community Ecology and Physiology
- Photosynthetic Processes and Mechanisms
- Methane Hydrates and Related Phenomena
- Epigenetics and DNA Methylation
- Genomics and Phylogenetic Studies
- Parasitic Infections and Diagnostics
- Magnetic and Electromagnetic Effects
- Chromosomal and Genetic Variations
- Microbial Inactivation Methods
- Enzyme Structure and Function
- Advanced Electron Microscopy Techniques and Applications
- Renal and related cancers
- Environmental DNA in Biodiversity Studies
- Cellular transport and secretion
- DNA Repair Mechanisms
- Glycosylation and Glycoproteins Research
- Micro and Nano Robotics
- Histone Deacetylase Inhibitors Research
- Coastal wetland ecosystem dynamics
- Bacteriophages and microbial interactions
- Heavy Metal Exposure and Toxicity
University of Georgia
2016-2025
University of Oxford
2023-2024
The Ohio State University
2010
Georgia Institute of Technology
2004-2008
J. Craig Venter Institute
2006
Centre de Recherche en Biologie cellulaire de Montpellier
2005
Centre National de la Recherche Scientifique
2005
Sine Institute
2005
Université de Strasbourg
2005
Sorbonne Université
2005
The ciliate Tetrahymena thermophila is a model organism for molecular and cellular biology. Like other ciliates, this species has separate germline soma functions that are embodied by distinct nuclei within single cell. germline-like micronucleus (MIC) its genome held in reserve sexual reproduction. soma-like macronucleus (MAC), which possesses processed from of the MIC, center gene expression does not directly contribute DNA to progeny. We report here shotgun sequencing, assembly, analysis...
Polyglutamylation of tubulin has been implicated in several functions microtubules, but the identification responsible enzyme(s) challenging. We found that neuronal polyglutamylase is a protein complex containing tyrosine ligase-like (TTLL) protein, TTLL1. TTLL1 member large family proteins with TTL homology domain, whose members could catalyze ligations diverse amino acids to tubulins or other substrates. In model protist Tetrahymena thermophila, two conserved types polyglutamylases were...
Mating Tetrahymena thermophila were bombarded with ribosomal DNA-coated particles at various times in development. Both macronuclear and micronuclear transformants recovered. Optimal developmental stages for transformation occurred during meiosis the micronucleus anlagen formation macronucleus. Evidence is given transient retention of introduced plasmid. Genetic molecular tests confirmed that sexually heritable was associated integration homologous site recipient chromosome.
The Cd 2+ -inducible metallothionein ( MTT1 ) gene was cloned from Tetrahymena thermophila . Northern blot analysis showed that mRNA is not detectable in the absence of , induced within 10 min its addition, expressed proportion to concentration, and rapidly disappears upon withdrawal. Similarly, when neo1 coding region flanked by noncoding sequences used disrupt locus, no transformants were observed number proportional increased concentration. neo3 cassette, which promoter replaced histone...
The in vivo significance of microtubule severing and the mechanisms governing its spatial regulation are not well understood. In Tetrahymena, a cell type with elaborate arrays, we engineered null mutations subunits microtubule-severing complex, katanin. We show that katanin activity is essential. net effect on polymer mass depends location. Although reduces destabilizes internal network microtubules, increases ciliary microtubules. also levels several types post-translational modifications...
Intraflagellar transport (IFT) trains, multimegadalton assemblies of IFT proteins and motors, traffic in cilia. To study how trains assemble, we employed fluorescence protein-tagged Chlamydomonas reinhardtii. IFT-A motor are recruited from the cell body to basal pool, assembled into move through cilium, disperse back body. In contrast this ‘open’ system, IFT-B retrograde reenter pool a portion is reused directly anterograde indicating ‘semi-open’ system. Similar systems were also observed...
Recently, we developed a mass DNA-mediated transformation technique for the ciliated protozoan Tetrahymena thermophlla that Introduces transforming DNA by electroporatlon Into conjugating cells (1). Other studies demonstrated neomycln resistance gene flanked H4-I regulatory sequences transformed homologous recombination within locus when mlcroinjected macronucleus (2). We describe use of conjugant electrotransformatlon (CET) replacement and development new independently replicating vectors...
In Tetrahymena, at least 17 distinct microtubule structures are assembled from a single primary sequence type of alpha- and beta-tubulin heterodimer, precluding distinctions among microtubular systems based on tubulin isotypes. Tetrahymena tubulins also modified by several types posttranslational reactions including acetylation alpha-tubulin lysine 40, modification found in most eukaryotes. axonemal numerous other microtubules acetylated. We completely replaced the gene macronucleus with...
Conjugating cells of the ciliate Tetrahymena thermophila were electroporated in presence plasmid DNA containing a paromomycin-resistant ribosomal RNA gene (rDNA). Cells selected with paromomycin following 12-24 hr growth on nonselective medium. Resistant appeared after 2-3 days. Processing vectors micronuclear rDNA and somatic macronuclear transformed cells, former yielding frequencies up to 900 transformants per microgram DNA. A protein (rpL29) conferring cycloheximide resistance also...
The genome of Tetrahymena thermophila contains 39 loci encoding NIMA-related kinases (NRKs), an extraordinarily large number for a unicellular organism. Evolutionary analyses grouped these sequences into several subfamilies, some which have orthologues in animals, whereas others are protist specific. When overproduced, NRKs three subfamilies caused rapid shortening cilia. Ultrastructural studies revealed that each NRK triggered ciliary resorption by distinct mechanism involved preferential...
Tubulin undergoes glutamylation, a conserved posttranslational modification of poorly understood function. We show here that in the ciliate Tetrahymena, most microtubule arrays contain glutamylated tubulin. However, length polyglutamyl side chain is spatially regulated, with longest chains present on ciliary and basal body microtubules. focused our efforts function glutamylation alpha-tubulin subunit. By site-directed mutagenesis, we all six glutamates C-terminal tail domain provide...
Dynein motors and regulatory complexes repeat every 96 nm along the length of motile cilia. Each contains three radial spokes, RS1, RS2, RS3, which transduct signals between central microtubules dynein arms. spoke has a distinct structure, but little is known about mechanisms assembly function individual spokes. In Chlamydomonas, calmodulin spoke-associated complex (CSC) composed FAP61, FAP91, FAP251 been linked to base RS2 RS3. We show that in Tetrahymena, loss either FAP61 or reduces cell...
Cilia, essential motile and sensory organelles, have several compartments: the basal body, transition zone, middle distal axoneme segments. The segment accommodates key functions, including cilium assembly activities. While contains doublet microtubules (incomplete B-tubules fused to complete A-tubules), only A-tubule extensions, its existence requires coordination of microtubule length at nanometer scale. We show that three conserved proteins, two which are mutated in ciliopathy Joubert...
We analyzed the role of tubulin polyglycylation in Tetrahymena thermophila using vivo mutagenesis and immunochemical analysis with modification-specific antibodies. Three five sites were identified at glutamic acids near COOH termini α- β-tubulin, respectively. Mutants lacking all on α-tubulin have normal phenotype, whereas similar β-tubulin are essential. A viable mutant three mutated showed reduced glycylation, slow growth motility, defects cytokinesis. Cells which if they cotransformed an...