Genetic analysis of resistance to bacterial pathogens in Arabidopsis thaliana

Zafia Anklesaria

Research Advisor: Dr. Jeffrey L. Dangl

Research Mentor: David Hubert

We study disease resistance in the model plant Arabidopsis thaliana. Plants detect specific bacterial pathogens and induce a resistance response that includes a localized programmed cell death termed Hypersensitive Response (HR), which limits the spread of the pathogen. A specific genetic interaction between a host Resistance gene (R) and pathogen avirulence (avr) gene triggers the defense response. The R protein RPS2 detects the effect of the avr protein avrRpt2 on a bridge protein called RIN4. AvrRpt2 cleaves RIN4 and thus activates RPS2 to trigger the defense response. Rin4kd plants have a mutation that reduces RIN4 expression and causes numerous developmental defects. I have screened for mutant plants that have the rin4kd mutation but lack these defects.  I am assessing whether these suppressor mutations fall in the RPS2 gene, and am examining the response of these plants to infection by bacteria containing the AvrRpt2 effector. Understanding the mechanism by which plants resist bacterial infection can help us reduce the loss of crops to disease. 

The design and application of a fluorescent reporter capable of testing the sufficiency of putative histone pre-mRNA processing factors.

Alexander Berkow

Research Advisor: Dr. William F. Marzluff

Research Mentor: Dr. Eric J. Wagner

The ability of three billion base pairs of DNA to fit into a cell's nucleus is largely dependent on a structure known as a histone.  The precise regulation of histone synthesis is required for proper DNA replication and cell division.  My research is concerned with how this regulation is affected by other proteins in the cell.

            Histone production is tightly linked with cell replication and growth, potentially playing a significant role in cancer progression.  Current chemotherapeutic drugs inhibit DNA synthesis and this in turn inhibits histone synthesis.  The reverse is likely true.  Future chemotherapy treatments could invovle the inhibition of histone sythesis thus inhibiting DNA synthesis and reducing tumor growth rate.  To achieve this, an in-depth knowledge of how histone synthesis is regulated within the cell will be essential.

Ryan Bialas

Research Advisor: Dr. Frank C. Church

Research Mentor: Dr.Yolanda Fortenberry

Biology Sponsor: Dr. Jason Lieb

A superfamily of proteins known as serine protease inhibitors, or serpins, acts by regulating serine proteases involved in numerous biological processes including degradation of the extracellular matrix, anticoagulation, fibrinolysis, inflammation, tissue repair, and atherosclerosis.  Recently it has been discovered that serpins can also interact with cysteine proteases.  My research focuses on exploring the interactions between the serpins Protein C Inhibitor (PCI) and Antithrombin III (ATIII), with the cysteine proteases Cathepsin-L and Papain.  Papain is a cysteine protease found in plants but with a very similar structure to the cathepsins.  Cathepsin-L is concentrated in the lysosomes of cells where it is involved in intracellular protein turnover.  Cathepsins are involved in the development of atherosclerosis and tumor cell metastasis.  This research is important because it will provide a better understanding of how serpins regulate cysteine proteases which could lead to possible preventive treatments for atherosclerosis and the spread of tumor cells.

Neurological pathways of mate selection

Suzanne Cavadel

Research Advisor: Dr. Keith Sockman

By testing levels of gene induction in European Starlings after they have been exposed to mating songs of varying quality, I hope to determine whether the noradrenergic system is sensitive to those songs and, therefore, potentially involved in mate selection. This project will help to identify the neurological pathways related to mate selection in songbirds, adding to the current model to understand how social information is integrated neurologically to the behavioral decision-making process.

Mechanisms of Oligonucleotide Targeting to a Double-Strand Break in Yeast

Godwin Chan

Research Advisor: Dr. Michael Resnick

Research Mentor: Francesca Storici

Biology Sponsor: Dr. Kerry Bloom

Repair of chromosomal double-strand breaks (DSBs) is essential to cell viability.  Inefficient or absent repair of DSBs due to mutations leads to myriad problems which include various cancers.  We explored the mechanism by which oligonucleotides with homology to both sides of a DSB can promote DSB repair in yeast.  The RAD52 gene is important for repairing a DSB by single strand oligonucleotides via a single-strand annealing (SSA) pathway.  However, the Rad51 protein suppresses oligonucleotide repair by promoting a competing pathway - recombination with a sister chromatid in haploid yeast and with the homologous chromosome in diploid yeast.  In the absence of RAD51, oligonucleotide repair increases.  Unfortunately, deletion of RAD51 produces sick strains

that are more susceptible to mutations, so the development of a method to suppress the function of Rad51 temporarily during oligonucleotide targeting to a DSB would be beneficial in avoiding the deleterious consequences of an absent Rad51 protein.

Genetic relatedness and its fitness effects in spadefoot toads

Hsin Chen

Research Adviser: Dr. Karin Pfennig

Research Mentor: George Harper

My research will examine the effect of genetic relatedness between mated pairs on their offspring's growth. Using spadefoot toads as my study system, I will use microsatellite DNA markers to assess relatedness between mated pairs of males and females. I will then determine if more closely related pairs produced offspring that grew more slowly in an experiment that measured offspring growth of the tadpoles from the mated pairs.  The results of this study will suggest whether females should take into account genetic similarity when choosing a mate.

Determination of minimal sequence of SLBP required for viability in D. melanogaster

Andy Courson

Research Advisors: Dr. William Marzluff and Dr. Robert Duronio

Research Mentors: Nehal Gulseren Cakmakci and Harmony Salzler

In all metazoans, including Drosophila melanogaster, histone mRNAs end in a conserved stem-loop rather than a polyA tail.  The stem loop is bound by a protein called stem loop binding protein (SLBP).  D. melanogaster SLBP (dSLBP) reaches its highest concentration during S phase, and is required for histone mRNA maturation.  The region of dSLBP required for processing is the last 110 amino acids starting at the RNA binding domain (RBD).  Experiments in other systems have shown that SLBP can facilitate the translation of histone mRNAs.  The minimal region required for translation of histone mRNA has been discovered in several vertebrates.  However, there is no significant homology outside of the RBD of vertebrates, sea urchins, and D. melanogaster.  The main goal of my project is to identify the minimal region of SLBP required for the translation of histone mRNA in D. melanogaster.  I postulate that this is one of the essential regions of SLBP for viability.

Effect of Lactobacillus gasseri on the gastrointestinal flora of mouse models

Kristin Ellis

Research Advisor: Dr. Deborah Threadgill

Research Mentor: Dr. Ian Carrol

Systematic Identification of Gene Order Polymorphisms in Yeast

Dina Faddah

Research Advisors: Dr. Jason Lieb, Dr. Todd Vision,

Research Mentor: Sean Hanlon

 Characterization of Mice Lacking the PAMP Peptide

Carrie Gibbons

Research Advisor: Dr. Kathleen Caron

Research Mentor: Ryan Dackor

Biology Sponsor: Dr. William Marzluff

Suppressor analysis of the nevershed mutant in Arabidopsis

Emilee Glaub

Research Advisor:  Dr. Sarah Liljegren

Research Mentors: Michael Lewis and Lalitree Darnielle

Abscission is an important mechanism through which plants shed organs such as flowers, leaves and fruits.   In Arabidopsis, abscission is characterized by the shedding of turgid floral organs through controlled cell separation.  The characterization of a predicted ADP-ribosylation factor GTPase activating protein (ARF GAP) required for floral organ shedding, NEVERSHED (NEV), has revealed a link between vesicle trafficking and abscission.  In order to further understand the pathway in which NEVERSHED acts, I carried out a screen for suppressors of the nev mutant.   Suppressors may fall into one of at least two categories:  (1) the gene product could interact physically with NEV as an extragenic suppressor or (2) an alternative pathway may be activated through a bypass suppressor.  My current aim is to identify the locus corresponding to the dominant S9 suppressor of nev, so that the role of vesicle trafficking in plant cell separation may be further explored.

The Role of cac1 and hir1 in the DNA Repair of Budding Yeast

Brian Graziano

Research Advisor:  Dr. Kerry Bloom

A cell's ability to recognize and repair DNA damage is critical to its well-being.  The failure of a cell to do so results in the rapid accumulation of mutations in successive generations, and such mutations often play a major role in the formation of tumors.  My research demonstrates that the proteins cac1 and hir1 are involved in the repair of double-stranded DNA breaks in budding yeast (Saccharomyces cerevisiae).  Knowledge of how DNA repair processes work in yeast will ultimately lead to a better understanding of how they function in humans.

The Promoter Region of Beta 1-Syntrophin

Lucy Guill

Research Advisor: Dr. Robert Sealock

Research Mentors:  Neal Kramarcy, Sushmita Jha, Anahit Mehrabyan

Biology Sponsor:  Dr. William Kier

Duchenne muscular dystrophy (DMD) is a skeletal muscle disorder resulting from mutations or deletions in the dystrophin gene.  DMD patients generally exhibit a decline in muscle function resulting from the weakening and degeneration of skeletal muscles.  The syntrophins are a family of proteins that interact with dystrophin, and are involved in the signaling cascade that controls muscle movement. Researchers currently working in the Sealock lab of UNC have observed an increase in beta 1-syntrophin levels in dystrophic mice.  Upregulation of this protein and other dystrophin associated proteins can lessen or ameliorate the effects of muscular dystrophy in mice.  I am investigating the 5' untranslated region of the beta 1-syntrophin gene in order to locate and sequence its promoter. Location of the beta 1-syntrophin promoter would lead to an

understanding of the expression of this gene, and how to upregulate it, furthering research into the development of a future treatment for muscular dystrophy.

Investigation of gene flow and genetic population structure in Lampropeltis pyromelana

Bo Han

Research Advisor: Dr. David Pfennig

Research Mentor: George Harper

Batesian mimicry occurs when a harmless species (mimic) closely resembles a harmful species (model) to derive protection from predators.  One would predict mimicry to fail in areas where the model is absent because predators that do not co-occur with the model will not be under selection to mistake the mimic as dangerous.  However, surprisingly, the geographical ranges of many mimics (including Lampropeltis pyromelana, Sonoran Mountain Kingsnake) extend beyond that of their models.  Why would L. pyromelana continue to mimic Micruroides euryxanthus (Arizona Coral Snake) in areas where the mimetic trait provides no protection and actually decreases survival?  I hypothesize that gene flow from areas where the model is present to areas where the model is absent may provide an answer.  My project uses mitochondrial DNA sequencing and phylogenetic analysis to understand the extent of gene flow in this species, which will clarify the perplexing evolution of the maladaptive mimetic trait.

Genetic Modifiers of Cystic Fibrosis Lung Disease

Barbara Kahn

 Research Advisor: Dr. Michael Knowles

Research Mentor: Rhonda Pace

Biology Sponsor: Dr. Lillie Searles

Cystic Fibrosis is a multi-system disease affecting the epithelial lining of tubular structures such as the airways, bile ducts, and pancreatic ducts.  Generally it is considered a recessive monogenic disorder caused by a mutation in the CFTR gene.  In fact, seventy percent of the CFTR alleles of patients with Cystic Fibrosis carry the same DF508 mutation.  However, the phenotypic variation amongst those suffering from Cystic Fibrosis covers a wide spectrum that cannot be explained by the CFTR genotype alone.  In an attempt to account for this disparity, it is hypothesized that modifier genes exist that affect the severity of the clinical findings in patients homozygous for the DF508 mutation.  In my project, genes related to inflammatory disease were selected as possible candidate modifier genes because they lead to pulmonary problems similar to those of Cystic Fibrosis.  Single nucleotide polymorphisms (SNPs) within each of the selected genes were chosen in collaboration with Roche Molecular.  I am looking for a correlation between any of the SNPs of the genes on the inflammatory disease panel and patients that are designated to exhibit mild or severe clinical features.  A significant correlation would lead to further research to examine the region of the gene containing the possible protective or detrimental modifier effect.

The Cell Cycle and Vascular Morphogenesis

Kim Kallianos

Research Advisor:  Victoria L. Bautch

Research Mentor:  Nick Kappas

During blood vessel formation, endothelial cells form branching vascular networks via cell division and cell migration.  The degree of cross-talk between these cellular pathways during blood vessel formation is not well understood.  Using a mouse embryonic stem cell model, I am examining blood vessel formation in order to quantify the relationship between cell division and migration.  To understand the interaction between these processes, I have decreased cell division in experimental clones by over-expressing the cell-cycle inhibitor p21.  By observing vessel morphology in the presence of fewer endothelial cells, I can examine the effect of decreased cell division upon vessel morphogenesis.  Understanding the process of blood vessel formation has important implications.  If we could more fully understand the forces affecting vessel formation, we could explore ways of inhibiting blood vessel growth toward tumors in order to treat aggressive cancers.

Isolation and characterization of a suppressor of a G-protein beta subunit mutant

Casey Kolb

Research Advisor: Dr. Alan Jones

Research Mentor: Erin Friedman

Heterotrimeric G proteins control an array of processes in cell and developmental biology.  Arabidopsis has become an important model system for the study of G proteins, because, unlike in animals, plants have just one G protein, which makes the study of G protein cellular pathways much simpler.  Many mutations in the G protein complex generate distinctive phenotypes in planta.  My project has revolved around a screen of EMS treated G protein beta-subunit mutants in an attempt to isolate a plant with a second, wild type-restoring mutation.  By growing the seeds in dark conditions, mutant suppressors were selected based on lengthened hypocotyls compared to the original mutants.  From over 30,000 plants screened, three potential suppressors have been selected.  One suppressor will be the focus of genetic mapping to locate and identify the EMS mutation.  Further study of phenotypic expression and responses to hormonal treatments has also been carried out.  From the isolated putative suppressors we hope to learn more about the roles that G protein signaling plays in plants.   

Electrophysiological Assessment of Auditory Sensory and Cognitive Processing in Autism

Amy Lambert

Research Advisors:  Dr. Odin van der Stelt

         Dr. Aysenil Belger

Biology Sponsor: Dr. Walter “Skip” Bollenbacher

Individuals with autism are often clinically reported to have atypical responses to sound.  However, the physiological and biological mechanisms of these idiosyncrasies are not well-understood.  To explore this issue, we used noninvasive scalp recordings of cerebral electrical activity to examine the auditory sensory and cognitive processing in children with autism and in typically-developing children of similar chronological age.  The recorded event-related potentials (ERPs) are used to determine whether the children with autism are characterized by deficits in their initial sensory detection, pre-attentive sensory discrimination, or attention-dependent cognitive discrimination.  This study provides a better theoretical understanding about deficits in auditory function in autism and may eventually hold implications for the assessment, diagnosis, and treatment of this neuropsychiatric disorder.

The effects of sympatry vs. allopatry on the mimic Lampropeltis triangulum elapsoides in comparison with the model Micrurus fulvius fulvius

Michelle Landstrom

Research Advisor: Dr. David Pfennig

Research Mentor: George Harper

Hybrid frequency of Spadefoot toads, Spea bombifrons and Spea multiplicata, and its relation to environmental conditions in the western United States.

Christina Lebonville

Research Advisor: Dr. Karin Pfennig

Research Mentor: George Harper

Project Description:  As a result of recent contact, two species of Spadefoot toads, Spea bombifrons and Spea multiplicata, have been observed to produce hybrid offspring.  If active mechanisms inhibit interbreeding between the two toads or if hybrid offspring are less fit than pure species, then the two species will remain separate entities.  However, if there are conditions under which hybrid offspring show greater or at least equivalent survivorship and fecundity, then the barriers preventing the species from merging break down.  If the frequency of hybrid offspring differs in varying environmental conditions, then determining the evolutionary fate of the two species will depend on identifying these conditions. We identified fixed genetic differences between the species and used them to identity pure species individuals and hybrids, both first generation and descendents of  hybridizations.    We then explored correlations between environmental conditions,  such as altitude, temperature and pond depth to name a few, and hybrid frequencies.

Copepods’ Resistance to Heat Stress

Heather Leisy

Research Advisor: Dr. Chris Willett

My experiment will examine the heat resistivity of the marine crustacean Tigriopus californicus, the copepod.  The populations used in this study are located in tidal pools in San Diego and Santa Cruz.  Survival rates of these two populations and the hybrids from the crossing of the two populations are compared after heat stressing at different temperatures.  The difference in survival rates tell about the general fitness of the different generations and also the relative geography of the two parental populations. Based on the results of the heat stress, a selection temperature for a second experiment involving genotyping the hybrids is chosen.  In this experiment, the hybrids that survived the heat selection will be compared to a control, non-selected group through use of PCR markers.  From these markers, a comparison of the more heat resistant ones to the less resistant will determine if the selected chromosomes have any effect on resistance. 

Effects of prenatal cocaine exposure upon 5-HT2A receptors in adult, female rats

Tom Lycan

Research Advisor: Dr. Josephine Johns

Biology Sponsor: Dr. Walter Bollenbacher

Abuse of the stimulant cocaine (benzoylmethylecgonine, C₁₇ H₂₁ NO₄ ) is a major social problem in the United States today, and is a major interest in the field of developmental psychobiology. The specific mechanisms by which cocaine affects the developing brain are for the most part unknown, including cocaine’s effect on levels of the monoamine neurotransmitter serotonin (5-HT). In rats, cocaine has been shown to affect the levels of 5-HT receptors in the brain differentially according to age, with a gender-specific decrease in 5-HT_1A receptor levels in male rats prenatally exposed to cocaine at postnatal day (PND) 60 accompanied by adverse behavioral effects. This experiment will investigate the effect of cocaine on 5-HT_2A receptors - which are similar in structure and function to 5-HT_1A receptors - in PND 60 female rats following prenatal cocaine exposure. These results will then be compared to data previously collected from female and male rats and rats of varying ages in order to determine the extent to which this effect is age and/or gender-specific.

Ena’s role in the regulation of the cytoskeleton during Drosophila oogenesis

James P. Mahaffey

Research Advisor: Dr. Mark Peifer

Research Mentor: Dr. Julie Gates

The Peifer Lab is interested in the regulation structural elements of the cell which provide the internal cellular framework and foundation for cell-cell adhesion. My project in the lab has been to characterize the function of a protein, Enabled (Ena), that regulates the actin cytoskeleton using a loss of function technique. Using confocal microscopy I have found that Ena is required for proper elongation of actin filaments in the developing ovary. Currently, I am following up these experiments to dissect the molecular pathways by which Ena’s function is regulated during Drosophila development. One protein that regulates Ena is the oncogene Abelson, and we are interested in how the physiological outcomes of mutations in Abelson could be attributed to perturbed Ena function.

Crypsis from above and below: the presence and possible mechanisms of countershading in the larva of two related amphibian species

Matthew McGee

Research Advisor: Dr. David Pfennig

Dark-light dorso-ventral coloration, often referred to as countershading, is a defining feature of many animal species. In aquatic systems, one of the proposed functions of countershading is to make the animal cryptic against both downwelling light filtering down from the water’s surface and against the darker substrate. In our study, we examine countershading in two related species of spadefoot toad, S. multiplicata and S. couchii, which co-occur within similar habitats in the American Southwest. Imaging data indicates that S. multiplicata possesses a greater degree of countershading than S. couchii, supporting the background matching hypothesis and illustrating a potential developmental tradeoff in the life histories of these two species.

The Contributions of Retrotransposons to the Evolution of New Genes in the Human Genome

Kamal Menghrajani

Research Advisor: Dr. Corbin Jones

Our research focuses on the contribution of gene duplications to the evolution of genes with novel functions. Initially, we are screening the human genome for genes copied and carried to other locations in the genome via retrotransposons. Subsequently, by comparison to the chimpanzee genome, we are analyzing the most recent of these events to see if they have contributed to the genomic differences among primates.

Dissecting the interaction between the type III effector AvrB and its target RIN4

Laura Musselwhite

Research Advisor: Dr. Jeff Dangl

Research Mentor: Dr. Darrell Desveaux

Defining Histone Modification Boundaries within Saccharomyces Cerevisiae

Rose O’Rourke

Research Advisor: Dr. Jason Lieb

Research Mentor: Bhargavi Rao

Nucleosomes may be thought of as a spool around which genomic DNA is wound.  They function to package DNA so that it can fit into cells, and they also serve to regulate access to the information encoded in DNA.  Nucleosomes consist of eight proteins called histones.  After they are produced, histones may be modified by the addition of small molecules that affect their function.  I am examining histone methylation.  Specifically, I am conducting experiments concerning the tri-methylation of lysine 4 on histone H3 and its relationship to the di-methylation of histone H3 lysine 36 within the budding yeast, S. cerevisiae.  These two marks abut each other within genes, and my experiments aim to determine if interdependence exists between these modifications in establishing the distinct boundaries between them.  Understanding the dependency among these histone modifications can reveal the mechanisms cells use to organize genomic information.

Characterization of the interaction between MutL and the helicase UvrD in the methyl-directed DNA mismatch repair pathway of E. coli

Steven Pattishall

Research Advisor: Dr. Steve Matson

Research Mentor: Adam Robertson

In order to reduce the mutations generated during DNA replication, protein pathways are used to check for and correct certain errors. The protein MutL works as a potential coordinator of the DNA mismatch repair system in the bacterium E. coli, as it enhances the activity of the helicase UvrD in its unwinding of DNA, among other functions. I have created a truncated MutL protein that can no longer appreciably stimulate UvrD, yet still seems to perform the other functions necessary for mismatch repair. Understanding the interaction between MutL and UvrD is important to understanding the pathway as a whole. Mutations in a MutL relative in humans is known to cause types of colorectal cancer, so better understanding this pathway could eventually lead to developments in cancer treatment in humans.

Molecular Phylogeography of Platystemon californicus (Papaveracea)

Nathan Poslusny

Serpentine soils are characterized by high concentrations of heavy metals and depleted nutrient levels. Plant adaptation to serpentine soils provides a convenient system to study the process of adaptive evolution in nature and the role of ecology in speciation.  I am studying the evolutionary history of serpentine colonization and gene flow in Platystemon californicus, an obligately outcrossing annual plant, by examining the patterns of genetic variation between serpentine and non-serpentine populations.  Specifically, I am sequencing three different nuclear introns in multiple individuals from 35 different populations in the western United States. These data will allow me to test the hypothesis that serpentine habitat has been colonized independently in different regions of California. 

Ecological Consequences of Hybridization in Spadefoot Toads

Alycia Reynolds

Research Advisor: Dr. Karin Pfennig

My research focuses on mating systems, sexual selection, and speciation in two species of spadefoot toads. These species both exist in the southwestern U.S., where they can breed in the same ponds. This creates the opportunity for hybridization. My research advisor and I created breeding pairs, which produced pure and hybridized tadpoles. By comparing the fitness of the hybrids to the pure tadpoles through behavioral and competition experiments, I explored whether hybrids have an ecological or genetic advantage or disadvantage, and therefore, whether it would be evolutionarily advantageous for these two species of toads to hybridize.

Understanding how speciation occurs and how species boundaries are maintained is a fundamental goal of evolutionary biology.  My research has and will provide direct evidence for how natural selection may or may not contribute to the maintenance of species boundaries.  Such research will therefore provide key insights into how biodiversity is generated and maintained.

Meiotic recombination in the Drosophila msh6 mutant

Mathilde Sabourin

Research Advisor: Dr. Jeff Sekelsky

Research Mentor: Sarah Radford

The process of meiotic recombination is important to the proper segregation of chromosomes during meiotic division, during which haploid gametes are formed.  During meiotic recombination, heteroduplex DNA is formed when strands from the homologous chromosomes come together in a single duplex.  Sequence differences between the homologous chromosomes in this heteroduplex DNA cause mismatches.  Mismatch repair is the process that fixes these heterologies.  In order to understand the structure of heteroduplex DNA in meiotic recombination, I have created a mutation in D. melanogaster MSH6, encoding a homolog of the E. coli MutS protein, which has been shown to act in mismatch repair.  The characterization of heteroduplex DNA in this mutant will aid in understanding the process of meiotic recombination.

Hybrid fitness and gene expression in spadefoot toads

Amber Somerville

Research Advisor: Dr. Karin Pfennig

My research has examined differences in gene expression between hybrid and pure bred spadefoot toads.  As with many animal systems, the hybrid Spea multiplicata and Spea bombifrons spadefoot toads show a reduced fitness when compared to their pure bred counterparts.  Much controversy surrounds whether these differences are genetic or ecological in nature.  My research has focused on specific genes that are inappropriately expressed in hybrids that may account for reduced hybrid fitness, including inviability and sterility.

Specialization for fast contraction in the tentacle muscle of the cuttlefish Sepia officinalis.

Michael P. Stella

Research Advisor: Dr. William M. Kier

Although muscle specialization has been studied extensively in vertebrates, less is known about the mechanisms modulating muscle performance that have evolved in invertebrate muscles. Research on squid muscle suggests that specialization for fast contraction involved changes in the arrangement and dimensions of the myofilaments, as opposed to biochemical changes. To begin to explore the generality of this mechanism in cephalopods, we are analyzing the transverse muscle of the tentacles of cuttlefish by transmission electron microscopy.

Role of Dietary Lipids on Breast Cancer Cell Migration

Meghan Valentine

Research Advisor: Dr. Frank Church

Biology Sponsor: Dr. Jason Reed

Research Mentor: Jennifer Carter

There is increasing epidemiological evidence linking the consumption of a high-fat Western diet and the incidence of breast cancer. Cancer risk increases as body weight rises. Diets high in monounsaturated and saturated fatty acids, ω-6 fatty acids, result in high rates of breast cancer. In contrast, people consuming diets rich in small ω-3 fatty acids have a lower incidence of breast cancer.  Many of these naturally occurring fatty acids in food are natural ligands to PPARγ.  PPARγ are ligand-activated transcription factors expressed by adipocytes and in several breast tumor cell lines/tissues. I am studying how natural ligands activate PPARγ and promote tumor cell migration and invasion in breast cancer cell lines.

The role of GAS 6 and Protein S in Mertk/Axl/Tyro3-mediated phagocytosis of apoptotic cells

Laura Vidales

Research Advisor:  Dr. Glenn Matsushima

Biology Sponsor: Dr. Mark Peifer

Proper clearing of apoptotic cells by macrophages is crucial in preventing the release of intracellular contents into the body, a process which can lead to the development of autoimmune disease.  The Mertk/Axl/Tyro3 family of receptor tyrosine kinases are important in the recognition and subsequent phagocytosis of apoptotic cells.  GAS 6 has been identified as the ligand for Axl and possibly for Mertk as well, while Protein S is the ligand for Tyro3, however the specific role of these two ligands has yet to be determined.  My research seeks to clarify the role that GAS 6 and Protein S play in phagocytosis of apoptotic cells.