An Analysis of Differentially Expressed Genes in the Context of Cochlear Malfunction in Charcot-Marie Tooth Syndrome
A goal of medicine is to better understand the relationship between disease and abnormal gene expression patterns. In order to better understand the genetically inherited disease, Charcot-Marie Tooth (CMT), we profile abnormally expressed genes throughout the development of the Trembler-J (TrJ) mouse carrying a mutation within the peripheral myelin protein-22 (pmp22). CMT is characterized by improper motor and sensorineural function of the peripheral nerves. Of particular importance to this study is the genetic variant, CMT1E, characterized by an additional deafness phenotype. We hypothesize that a genetic defect in PMP22 causes abnormal regulation and expression of genes central to proper tissue development, that in turn accounts for the neuropathic phenotype and cochlear malfunction of CMT1E. PMP22 is a 22-kDa transmembrane protein that is highly expressed in neural tissue and to a lower extent in nonneural tissues at critical developmental time points. At least 61 point-mutations within PMP22 are linked to a neuropathology, 9 of which cosegregate with CMT1E and the deafness phenotype, and prove useful in defining structural properties of PMP22 important in cochlear function. Using the TrJ mouse model for CMT, we have isolated and characterized a set of cochlear genes that are differentially expressed relative to functional levels of PMP22. We quantified expression patterns of candidate genes with functions central to auditory development in nonneural tissues at ten prenatal and postnatal developmental points. With our findings, we developed a preliminary model of gene-interactions that may help explain the role of a PMP22 mutation in the development of auditory dysfunction.
Biological and Environmental Sciences, University of Tennessee at Chattanooga, Chattanooga, TN
Identification of Conotoxin Genes From the Cone Snail Conus pennaceus
Conotoxins are produced by large group of predatory marine snails, Cone Snails. This group of snails inhabit tropical reef environments throughout the world. They are categorized into three major groups based upon prey preference, 1) the piscivorous group prey upon fish; 2) molluscivorous group prey upon mollusk; and 3) vermivorous group prey upon polychaete annelids. All cone snails are venomous predators whose venom contains highly toxic peptides that immobilize and capture prey items. The toxic proteins are produced in long ducts and are stored in venom bulbs. It is estimated that more than 50,000 unique peptide sequences exist in cone snail venom. The cellular targets for these peptides include voltage and ligand gated ion channels and G-protein coupled receptors. Because of the large number toxins found in a single species of snail it is of interest to catalog the different toxin genes for each snail and predict the protein sequence in order to properly classify the toxins. Using conserved sequences in the signal sequence and the poly-A tail of mRNA to prepare primers, reverse transcriptase PCR was utilized to prepare cDNA of toxin genes. The potential genes were then sequenced. Analysis of the DNA sequence allowed for identification of open reading frames and putative peptides that could be compared to known conotoxin sequences.
Dept of Biology, Francis Marion University, Florence, South Carolina
P60 • Breanna Willeford, Sierra Willeford, Duncan Perry, Tianyi Wu, Fang Ju Lin
Effect of Grape Seed Extract in Fruit Fly Drosophila Huntington’s Disease Model
Huntington’s disease is a devastating neurodegenerative disorder, affecting 4-8 per 100,000 in U.S. population. Most patients show deficits in cognitive and motor function starting at age 35 to 45. Mutant huntingtin protein with polyglutamine expansion form protein aggregation which leads to cell death. It has been reported that grape seed extract (GSE; 2.8 μg/ml) extends the lifespan of transgenic Drosophila carrying a mutant human huntingtin gene. In addition, GSE also improves motor function in the mouse Huntington’s disease model. In this study, flies were subjected to a ten-fold concentration (30 μg/ml) of GSE compared to previous report. The effects of GSE were observed on their motor function by climbing assay, as well as on their lifespan. The morphological change in fly brain was examined by immunohistochemistry. We aim to develop a valid screening using Drosophila for potential compounds that could slow down the progression of disease, as currently there is no cure for Huntington’s disease.
Dept of Biology, Coastal Carolina University, Conway, SC
P61 • Gregory S. Barrett, Diana B. Ivankovic, Donna R. Weinbrenner
Crude extracts taken from Phytolacca americana were tested on the neuronal morphology of the rat derived pheochromocytoma (PC12) cell line. The extracts were prepared using the Soxhlet extraction method with extraction times of 20-24 hours using methanol, deionized distilled water, and methylene chloride for solvents. Extractions were performed on separate plant materials which included leaves/stems, mature berries, and roots. These crude extracts were added to cell growth medium at varying concentrations then applied to the differentiated neuronal model (100ng/ml Nerve Growth Factor for 48 hours) of the PC12 cell line while being sub-cultured on 96 well ELISA plates coated with rat tail collagen type IV. Extracts were allowed to incubate for 48 hours before MTS cell viability assays were performed.
P62 • Ombeni M. Idassi1, Patrice Cagle1, Ipek Goktepe3, Patrick Martin1, Radiah Minor2
