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Jones, Alan M.

May 4, 2011

Selected References   |   Curriculum Vitae  |   Open Positions  |   Currently Seeking Postdocs  |
Dept. Pharmacology Web Page | Potential Students Interested in Joining the Lab

We are interested in cell-to-cell communication. At present, our efforts are focused on signaling that depends on the heterotrimeric G protein complex. Much of our work is devoted to understanding novel mechanisms for activating this pathway therefore we are looking at organisms quite divergent to animal cells where much is already understood about G protein signaling. Using the diversity of life to discover the diversity of cell signaling is a powerful approach.

The JonesLab showed that most eukaryotic cells outside of the animal group have a very different mechanism for activation mechanism. Whereas, the rate-limiting step for G protein activation is nucleotide exchange on the Galpha subunit of the complex, in plant cells and protists, this step is spontaneous. Therefore, the need for a G protein coupled receptor to catalyze this GTP for GDP nucleotide exchange is not needed in plant cells and protists. We showed that the reaction that returns G protein activation (GTP-bound) to the inactive state is the rate-limiting step and is mediated by a receptor like protein that accelerates this “off” reaction. However, this is not the only mechanism to control the pool size of the activated G protein. The JonesLab takes a wide variety of experimental and theoretical approaches to solve central basic problems in cell biology with the intent that our work will translate into improved quality of life, create sustainable agriculture, and make us better stewards of the Earth. Mathematical modelers, biochemists, microscopists, physiologists, geneticists are welcomed to join the JonesLab team. Please see the available positions by clicking the link above.

The “G” cycle of animal vs. Arabidopsis
(A) G protein regulation in mammalian cells. In the absence of ligand, G protein forms an inactive heterotrimer with GΒγ dimer (left bottom). Ligand-bound GPCR promotes GDP dissociation and GTP binding on G protein (Top). GTP-bound GΒ dissociates from GΒγ dimer, and both activated GΒ and freely-released GΒγ modulate activity of the effectors (right bottom). GΒ hydrolyses GTP to GDP, and re-binds to GΒγ to return to its inactive state. (B) G protein regulation modeled in Arabidopsis. Arabidopsis G protein (AtGPA1) can spontaneously dissociate GDP and activate itself (left bottom). AtGPA1 does not hydrolyze its GDP rapidly, however AtRGS1, a 7TM-RGS protein, promotes the GTP hydrolysis of AtGPA1 (top). D-glucose or other stimuli functions on AtRGS1 directly or indirectly, and decouples AtGPA1 from AtRGS1 (right bottom). Once released from AtRGS1, AtGPA1 does not hydrolyze its GTP efficiently, maintaining its active state, and modulating the effector activities.

Copenhaver, Gregory P.

May 3, 2011

The genome of any organism is an amazing piece of biology. It is a highly efficient and adaptive information storage, delivery and retrieval device capable of propagating, modifying and repairing itself. As such, understanding how genomes function is central to a broad range of disciplines including genetics, cell biology, biochemistry, developmental biology, and evolution. At the broadest level our lab is interested in understanding how the constituent parts of a genome, chromosomes, function and the dynamic processes that influence them.

To achieve this goal we primarily use the model flowering plant Arabidopsis thaliana. Arabidopsis has a number of characteristics that make it a great organism to study fundamental biological principles. It has a small “completely” sequenced genome with only five chromosomes. It is readily amenable to genetic, cytological and biochemical experimental approaches and it’s near world-wide distribution makes the use of natural variation a powerful tool. Also, here in the biology department at UNC-CH there is a particular emphasis on the use of Arabidopsis as a model system.

My lab is primarily interested in understanding how meiotic recombination is regulated at the genomic level in higher eukaryotes. While significant progress has been made in understanding many of the molecular components of the recombination process in lower eukaryotes like the yeast S. cerevisiae, far less is known about similar functions in complex multi-cellular organisms. Because of the complexity of higher eukaryotic genomes, the high level of gene duplication and divergence, the presence of DNA modification and the organization of multiple chromosomal domains into heterochromatin the molecules that govern meiotic recombination in these organisms are likely to be novel and of significant biological interest. Additionally, their identification may have practical benefits, contributing to our understanding of human disease genes and providing useful tools for agricultural bioengineering.

A second research area in the lab is investigating the role of centromere DNA in chromosome biology. Centromeres are the chromosomal domains that direct segregation during cell division by mediating a number of critical functions including: attachment of the chromosomes to the spindle microtubules, nucleation of kinetochore proteins, and maintenance of sister chromatid cohesion. Arabidopsis centromeres are some of the best characterized among higher eukaryotes. Currently the efforts in the lab are focused on obtaining a complete definition of the DNA within the genetically defined centromeres of Arabidopsis.

Grant, Sarah R.

May 3, 2011

Interaction of plants and microbes. I no longer supervise students or postdoctoral fellows. I remain a member of Jeff Dangl’s research group. The Dangl group investigates the plant immune system and its influence on the communities of environmental microbes associated with plants.

See publications here.

Gensel, Patricia G.

April 28, 2011

Pat Gensel’s research emphasizes the study of fossil plants of Devonian age, with the goals of contributing data about their morphology, structure, evolutionary relationships, and overall patterns of evolutionary change. She also conducts research on plants of Lower Carboniferous age, with the intent of better understanding whole plants, phyletic lines, and evolutionary change in the time immediately following the Devonian. Research on plants of Late Cretaceous age from North Carolina is also underway, particularly on conifers and angiosperm wood; collections of leaves and flowers await study — this is a period of time of radiation of early angiosperm groups and this region has been little studied for over 50 years. She is interested in plant morphology, pteridology, and palynology, especially aspects of in situ Devonian spores, stratigraphic applications, and the use of pollen or spores in systematic and phylogenetic analyses in modern and fossil plants.