Student Publications and Presentations
Permanent URI for this collectionhttps://hdl.handle.net/2104/10219
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Browsing Student Publications and Presentations by Subject "C. elegans."
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Item Characterization of Hemicentin in C. elegans(2020-04-21) Ahumada, Abraham; Haworth, Emma; Ross, Kylie; Sowinski, Halee; Antony, Keerthi; Myeongwoo, Lee; Baylor University. Dept. of Biology; Baylor University.; Baylor University. Dept. of BiologyCharacterization of Hemicentin in C. elegans Emma Haworth, Kylie Ross, Halee Sowinski, Keerthi Antony, Abraham Ahumada Department of Biology, Baylor University, One Bear Place 97388, Waco, TX 76798, U.S.A In the nematode, Caenorhabditis elegans, the him-4 gene linked to the X chromosome encodes hemicentin protein, a component of the extracellular matrix (ECM), which is characterized by 45 immunoglobulin repeats, and fibulin-like domains. The ECM is a three-dimensional network composed of proteins and sugars deposited outside of the cell. ECM proteins are typically large, glycosylated, and contain repeats and motifs for cell binding. Hemicentin is specifically present in the basement membrane (BM), a special sheet-like ECM, that plays an important role in cell migration and tissue attachment, and stability of mitotic germ cells. HIM-4 contains six RGD motifs, a protein sequence specific to the integrin binding receptor. In the following study, CRISPR gene editing was used to create mutations in him-4 at two of the six RGD sequences. These sequences were targeted to replace the D amino acid (Aspartic Acid) with the E amino acid (Glutamic Acid). This mutation in him-4 causes defective phenotypes related to cell binding. We have isolated several targeted animals with tissue fragility, suggesting that the RGD sequence is vital for the function of the protein; the gene editing may interfere with hemicentin binding to the integrin receptor. The disruption of the ECM causes improper attachment of the gonad BM to epithelial BM leading to the hemorrhaging of the gonads and the intestines in C. elegans. The observation of the hemorrhaging phenotype and the single-worm PCR will be used to detect CRISPR-induced homozygous alleles. This research may allow for further studies on gonad development and human orthologs of the hemicentin protein. The connection between the hemicentin protein and the ECM deformities may offer insight into diseases associated with tissue fragility.Item Genetic screening for suppressor mutation in Caenorhabditis elegans odr-3 mutants(2020-04-21) Carroll, Jacqueline; Badra, Anthony; Cantu, Analisa; Conway, Caitlyn; Diaz, Ashley; Gunderson, Annika; Lee, Myeongwoo; Baylor University. Dept. of Biology; Baylor University.; Baylor University. Dept. of BiologyA suppressor mutation is a mutation that negates the effects of a different, separate mutation, facilitating a return to the wild-type phenotype. In this experiment, a suppressor mutation screen of a mutation of the odr-3 gene was conducted by observing the egg-laying behaviors of mutagenized Caenorhabditis elegans worms in different chemical stimulants, and comparing the results to the wild-type. A mutant with a successful suppressor mutation of an odr-3 mutation will have similar egg laying behaviors to that of the wild-type (N2). The gene, odr-3, encodes a G protein α subunit that plays an integral role in sensory and olfactory neurons. The role odr-3 plays is vital to olfactory sensation, osmoregulation, and mechanosensory function. In this experiment, two worm lines that each had an odr-3 mutation and a potential suppressor mutation were generated, isolated, and tested: odr-3-JC-17 and odr-3-JC-66. When serotonin was introduced, the odr-3-JC-17 mutant strain showed a similar response in egg laying compared to the wild type, N2. The average number of eggs laid in an hour for each of the N2, odr-3, odr-3-JC-17 and odr-3-JC-66 strains in serotonin solution were 0.18 0.33, 0.21, and 0.44 eggs/hour, respectively. In dopamine solution, odr-3-JC-17 demonstrated similar egg laying behavior to N2. In a dopamine solution, the N2, odr-3, odr-3-JC-17 and odr-3-JC-66 strains laid 1.04, 2.25, 1.29, and 0.40 eggs/hour, respectively. When placed in an imipramine solution, odr-3-JC-17 had a significantly higher value of eggs laid in an hour than the odr-3 mutant. In imipramine solution, the N2, odr-3, odr-3-JC-17, odr-3-JC-66 mutant strains laid 1.56, 1.53, 2.80, and 0.91 eggs/hour, respectively. These results indicate the presence of a suppressor mutation that is at least partially effective in the odr-3-JC-17 mutant strain.Item Targeting RGD cell-binding motif of LAM-3 and its effects on ECM(2020-04-21) Nichols, Erika; Dinh,Kyle; Han, Mark; Lishewski, Matt; Root, Jessica; Taylor, Megan; Lee, Myeongwoo; Baylor University. Dept. of Biology; Baylor University.; Baylor University. Dept. of BiologyTargeting RGD cell-binding motif of LAM-3 and its effects on ECM Kyle Dinh, Mark Han, Matt Lishewski, Erika Nichols, Jessica Root, Meg Taylor, Zhongqiang Qiu Baylor University Biology Dept. Laminin is a protein composed of α, β, and γ chains and is present in basement membrane ECM. lam-3 is an α subunit which is essential in the formation of the basement membrane. It is highly expressed in the cell surroundings of the alimentary, epithelial, excretory, muscular, and nervous tissues. Mutations in the LAM-3 of C. elegans may cause pathological conditions of improper cell adhesion, migration, and signal-receptor pathways. Integrins are the extracellular matrix receptors that facilitate bidirectional signaling at the membrane surface. The specificity of this ligand-receptor interaction is based upon specific characteristics of the cell binding motif. The RGD is a binding motif synthesized of a tripeptide including Arginine-Glycine-Aspartate. Mutations in the RGD binding site will result in obvious inhibition of cell binding to the protein. A mutant C. elegans strain containing RGD to RGE mutation in lam-3 gene has been created by injecting a CRISPR-Cas9 mutation specific to the RGD site. This mutation induced a change from aspartic acid (D) to glutamic acid (E). We injected forty-nine N2 C. elegans and obtained one positive homozygote clone verified with a single-worm PCR. Further confirmation will be conducted in the coming weeks with comparison by thrashing assays as well as DNA sequencing of the positive homozygotic mutant. The identification of this homozygotic phenotype may directly relate to the human ortholog of LAMA-2 and potential treatment of the human muscular dystrophy.