Genetic Processes Commons^™

Dual Mechanisms Implemented By Lin-28 For Positive Regulation Of Hbl-1 Are Necessary For Proper Development Of Distinct Tissues In Caenorhabditis Elegans, Madeleine Minutillo

Graduate School of Biomedical Sciences Theses and Dissertations

In Caenorhabditis elegans, the heterochronic pathway is comprised of a hierarchy of genes that control the proper timing of developmental events. hbl-1 (Hunchback Like-1) encodes an Ikaros family zinc-finger transcription factor that promotes the L2 stage cell fate events of the hypodermis. The downregulation ofhbl-1 is a crucial step for the transition from the L2 to the L3 stage. There are two known processes through which negative regulation of hbl-1 occurs: suppression of hbl-1 expression by 3 let-7 miRNAs through the hbl-1 3’UTR and inhibition of HBL-1 activity by LIN-46. The mechanisms by which hbl-1 is positively regulated have not …

Replication-Transciption Switch In Human Mitochondria, Karen Agaronyan

Graduate School of Biomedical Sciences Theses and Dissertations

Coordinated replication and expression of mitochondrial genome is critical for metabolically active cells during various stages of development. However, it is not known whether replication and transcription can occur simultaneously without interfering with each other and whether mtDNA copy number can be regulated by the transcription machinery. Human mitochondrial RNA polymerase (mtRNAP) is a central enzyme involved in gene expression in mitochondria. It generates genome-size polycistronic transcripts and also makes replication primers at two origins of replication. MtRNAP is distantly related to phage T7 RNAP. While T7 RNAP is optimized to produce large amounts of transcripts to overcompete the bacterial …

The Genetic Hierarchy Of The Heterochronic Pathway In C. Elegans, Jennifer Tsialikas

Graduate School of Biomedical Sciences Theses and Dissertations

The correct timing of developmental events is fundamental to the growth of every animal. The pathways that control developmental timing and cell-fate succession are complex and robust in a way that underscores this importance. In this work, I have shown how an early developmental regulator, LIN-14, acts to integrate the earliest aspects of development with the events that take place afterward. I have uncovered how microRNAs from two different families fit into the cascade of proteins and micro RNA regulation that defines the developmental timing pathway. Finally, my work has helped to uncover the dual-acting nature of two proteins in …

Microrna-Target Interactions In Embryonic Stem Cells, Shuang Wu

Graduate School of Biomedical Sciences Theses and Dissertations

Animal embryogenesis is a highly orchestrated process involving many geneexpression programs that determine specific fates of individual cells during development. Gene expression can be regulated at different stages such as at transcription initiation or mRNA stability, and microRNA-mediated gene regulation is a crucial pathway on the regulation of mRNA stability. microRNAs, or miRNAs, are small, conserved non-coding RNAs that negatively regulate gene expression post-transcriptionally. The mouse miR-290-295 cluster and its human homolog miR-371-373 are stem cell-specific miRNA clusters, and their expression can only be observed in early embryos, primordial germ cells, germ cell compartments of adult testis and embryonic stem …

Assembly And Structure Of Human Mitochondrial Transcription Initiation Complex, Yaroslav Morozov

Graduate School of Biomedical Sciences Theses and Dissertations

Mitochondria play a key role in energy metabolism in nearly all eukaryotic cells. Apart from that, they participate in many other biochemical pathways, such as amino acid and nucleotide metabolism, and biosynthesis of cholesterol, heme, and iron-sulfur clusters. Mitochondria are also involved in cell signaling, apoptosis and regulation of cell cycle. Abnormalities of mitochondrial morphology and function are often associated with tumor progression, neurodegeneration and aging.

Mitochondria are unique organelles in mammalian cells because they have their own genomic DNA, transcription and translation systems. Various mutations and defects in mitochondrial gene expression lead to severe diseases that include various mitochondrial …

The Development Of A Platform For Expression And Purification Of The Mammalian Transmembrane Transporter Abca4, Amaryllis Ortiz

Graduate School of Biomedical Sciences Theses and Dissertations

Purpose- ABCA4 is an ATP Binding Cassette (ABC) protein localized at cone and rod photoreceptor outer segments of the retina. Though mutations in ABCA4 have been found to cause a broad spectrum of disorders, ABCA4's high molecular weight (~210 kDa) and biochemical transmembrane properties have made ABCA4 functional studies unsuccessful. Identifying how ABCA4 functions might have significant clinical impact and open unanticipated avenues for therapeutic interventions. Thus, the objective of this study was to develop a new expression system able to produce the full-length, correctly folded and fully functional ABCA4 protein.

Methods- the ABCA4 gene was amplified from the PCMV6-ABCA4 …

Structural And Functional Interactions Between Bro1 Domain Of Human Alix Protein And Nucleocapsid Packaging Rna Complex From Hiv, Scott Gross

Graduate School of Biomedical Sciences Theses and Dissertations

A virus is only as powerful as its ability to spread. Enveloped retroviruses, namely HIV-1, use exocytosis pathways that normal host cells use to release particles from the plasma membrane. The main pathways of interest in this study are the Endosomal Sorting Complex Required for Transport (ESCRT) and adjacent ALIX pathways. The ESCRT pathway is especially important for degradation of receptor/cargo complexes that form Multi-Vesicular Bodies (MVBs). Currently, there is no known therapy that targets this endosomal pathway, which would prevent the spread of the virus to other cells. The virus has adapted to jump from pathway to pathway when …

Analysis Of The Regulation And Function Of Cip2a To Identify Candidate Biomarkers For Prostate Cancer, Diana Savoly

Graduate School of Biomedical Sciences Theses and Dissertations

Protein Phosphatase 2A (PP2A) is a tumor suppressor involved in the regulation of several signaling pathways and the cell cycle. PP2A becomes inactivated by several inhibitors, including Cancerous Inhibitor of PP2A (CIP2A). CIP2A has been identified as an oncogene, which is over-expressed in cancers and inhibits PP2A through direct interaction. CIP2A is recognized as a biomarker for cancer; however, it is not cancer-specific. Therefore, we identified and examined the use of CIP2A-regulated proteins as potential biomarkers in prostate cancer to better diagnose prostate cancer in patients. Currently, Prostate Specific Antigen (PSA) is widely used to detect prostate cancer; however, it …

Generation And Characterization Of Peptide Fusion Proteins, Brianna L. Probasco

Graduate School of Biomedical Sciences Theses and Dissertations

Pathogenic Th17 cells drive progression of many autoimmune diseases. Th17 cells develop from naïve T cells in the immune system after antigen-driven stimulation in a specific cytokine environment. Normally, T cells act to fight off infection, but when not properly controlled, they can cause disease. The cytokine interleukin-23 (IL-23) plays an essential role in the expansion of pathogenic Th17 cells. IL-23 is a heterodimeric protein, composed of a p19 alpha chain and a p40 beta chain. The p40 is also part of IL-12 and binds to the IL-12 receptor beta 1 (IL-12Rβ1) subunit. Thus, it follows that the IL-23 receptor …