Genetics and Genomics Commons^™

Development Of Reverse Genetics Tools In The Two-Spotted Spider Mite Tetranychus Urticae, Nivitha Bhaskar

Electronic Thesis and Dissertation Repository

Tetranychus urticae, commonly known as the two-spotted spider mite, poses a significant threat to agriculture due to its ability to feed on a diverse range of plant hosts and its strong detoxification abilities in overcoming xenobiotic response. With global warming projected to increase spider mite infestations, it is vital to study the detoxification genes that enable the mite to adapt and survive. The spider mite genome sequence reveals a unique set of detoxification genes that can be studied using RNAi as a promising reverse genetic tool. However, the current genetic toolkit requires improvement. This study examined the effectiveness of …

Characterizing Endogenous Dicer Products To Unravel Novel Rnai Biogenesis Pathways, Jacob Oche Peter

Dissertations

ABSTRACT

RNA interference (RNAi) is a pervasive gene regulatory mechanism in eukaryotes based on the action of multiple classes of small RNA (sRNA). Exploiting RNAi pathways in non-model systems have great potential for creating potent RNAi technologies. Here, we accessed RNAi-mediated control of gene expression in the two-spotted spider mite, Tetranychus urticae (T. urticae) using engineered dsRNA designed to modulate the host RNAi pathway and increase RNAi efficacy. Analysis of Dicer (Dcr) generated fragments revealed how exogenous RNAs access the host RNAi pathway in this animal, opening avenues for designing RNAi technology for their control. Further, some organisms …

A Context-Forward In Vivo Functional Genomics Platform For Target Discovery And Establishing Vulnerability Context In Pancreatic Cancer, Johnathon Rose, Johnathon Lynn Rose

Dissertations & Theses (Open Access)

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive malignancy with a very poor patient prognosis (5-year survival of ≤ 7%). While transcriptional profiling has aided in the classification of this disease into at least two broader subtypes, this alone has so far been insufficient to inform on more nuanced patterns of oncogenic dependency. We hypothesized that a more comprehensive and granular characterization of PDAC disease diversity is required to establish relevant context for targeted therapy. To this end, we sought to establish an integrated platform to: i) more comprehensively characterize differential oncogenic signaling across our tumor models, and ii) establish …

Identification Of Novel Host Genes Required For Antiviral Immunity And Viral Genome Replication In C. Elegans, Fei Meng

LSU Doctoral Dissertations

RNA interference (RNAi) is a wide-spread gene silencing mechanism that control diverse biological functions and triggered by small interfering RNAs (siRNAs) processed from the viral genome or its replication intermediates. Mechanistic studies of antiviral RNAi in Caenorhabditis elegans has led to the identification of several critical factors involved in the process. As a result, whether antiviral RNAi requires additional novel genes remains to be an open question.

Viruses are intracellular parasites that rely on host products for reproduction. Disrupting their interaction with host factors can significantly compromise their replication and keep them under control. Thus, identification of host genes …

Fate Of Ingested Rna In The Two-Spotted Spider Mite, Obrie D. Scarbrough

Honors Theses

RNA interference, or RNAi, is a gene regulation mechanism that uses small noncoding RNAs (sRNAs) to silence the expression of certain genes. The application of RNAi has been extended to insect pest control. The two-spotted spider mite Tetranychus urticae is a persistent agricultural pest that tends to develop pesticide resistance at an alarming rate, making it a perfect candidate for RNAi technology development. It was hypothesized that unique sRNAs could be isolated from RNA soaked spider mites, and new synthetic RNAs could be synthesized to elicit greater knockdown than was achieved in previous studies. To perform this research, a small …

Targeted Germ Cell Knockdown Of Xlr3 In Mus Musculus, Caity Miller

Honors Scholar Theses

The X chromosome is rather distinct from autosomes due to the unique regulatory and functional characteristics it exhibits. Xlr3 is just one gene in a superfamily of highly related, and homologous genes found on the X chromosome in mice. Xlr3 is part of a complex, imprinted locus, of which the function is not well understood, although its protein product can be found in testis and oocyte. However, it is theorized that the region may be implicated in the progression of meiosis, due to localization of XLR3. This study sought to characterize the function of Xlr3 through the use of a …

Cohesion Without Cohesins In Drosophila Meiosis, Avik Mukherjee

Doctoral Dissertations

Meiosis is essential for sexual reproduction. The proper segregation of chromosomes in meiosis requires multiple functions of a multi-subunit protein complex known as cohesin. Cohesin forms a ring around duplicated sister chromatids and prevents them from separating prematurely. In Drosophila, mitotic cohesin is composed of four subunits: SMC1 and SMC3 and SCC1/RAD21 and SCC3/SA and are required for mitotic cohesion. However, RAD21 is dispensable for meiotic cohesion and although SMC1 and SMC3 are present on meiotic centromeres and on synapsed chromosome arms, as expected, their functions in meiosis remain poorly characterized. Moreover, unlike in other eukaryotes in which screens for …

Characterization Of Induced Rnai Silencing Of Vaccinia Virus Essential Genes, Kewa Jiang

Honors Scholar Theses

Vaccinia virus (VACV) is a large double-stranded DNA virus and the prototypical member of the family Poxviridae and is most notable for its use as the vaccine that eradicated smallpox (variola virus). More recently, VACV has been used to develop recombinant vaccines and immunotherapies. However, many of these processes require VACV replication to be tightly controlled. RNA interference (RNAi) is a powerful tool for in vitro silencing of mRNAs that are complementary to 19-21 base pairs (bp) of double-stranded RNA (dsRNA). This project outlines the design and preliminary analysis of two inducible RNAi silencing constructs targeting multiple VACV essential genes …

Staufen Negatively Modulates Microrna Activity In Caenorhabditis Elegans, Zhiji Ren, Isana Veksler-Lublinsky, David Morrissey, Victor Ambros

Victor R. Ambros

The double-stranded RNA-binding protein Staufen has been implicated in various post-transcriptional gene regulatory processes. Here we demonstrate that the Caenorhabditis elegans homolog of Staufen, STAU-1, functionally interacts with microRNAs. Loss-of-function mutations of stau-1 significantly suppress phenotypes of let-7 family microRNA mutants, a hypomorphic allele of dicer and a lsy-6 microRNA partial loss-of-function mutant. Furthermore, STAU-1 modulates the activity of lin-14, a target of lin-4 and let-7 family microRNAs, and this modulation is abolished when the 3' untranslated region of lin-14 is removed. Deep sequencing of small RNA cDNA libraries reveals no dramatic change in the levels of microRNAs, or other …