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Full-Text Articles in Biochemistry, Biophysics, and Structural Biology

Dicer Represses Antiviral Innate Immunity Pathways In Mouse Embryonic Stem Cells, Chandan Gurung Dec 2021

Dicer Represses Antiviral Innate Immunity Pathways In Mouse Embryonic Stem Cells, Chandan Gurung

Dissertations

Recent studies have demonstrated that embryonic stem cells (ESCs) are deficient in expressing type I interferons (IFN), the cytokines that play key roles in antiviral responses. However, the underlying molecular mechanisms and biological implications of this finding are poorly understood. In this study, I used a synthetic RNA-based assay that can simultaneously assess multiple forms of antiviral responses in ESCs. Dicer is an enzyme essential for RNA interference (RNAi), which is used as a major antiviral mechanism in invertebrates but not clear in vertebrates. RNAi activity is detected in wild-type ESCs but is abolished in Dicer knockout ESCs (D−/−ESCs) as …


Molecular Mechanism Of Action Of The Natural Polyphenolic Compound And The P300 Inhibitor “Carnosol” Against The Triple Negative Breast Cance, Halima Ali Mohammed Salem Alsamri Nov 2021

Molecular Mechanism Of Action Of The Natural Polyphenolic Compound And The P300 Inhibitor “Carnosol” Against The Triple Negative Breast Cance, Halima Ali Mohammed Salem Alsamri

Dissertations

Carnosol, a naturally occurring Phyto polyphenol found in sage, oregano, and rosemary, has been extensively studied by our laboratory for its anticancer effects in various types of cancer. In human Triple-Negative Breast Cancer (TNBC), carnosol was shown to inhibit cellular viability, colony growth, induced cell cycle arrest, autophagy, and apoptosis. Nonetheless, very little is known about the molecular mechanism of action. In the current study, the ability of carnosol to inhibit metastasis and tumour growth was examined. Wound healing and invasion assays revealed that carnosol inhibited migration and invasion at non-cytotoxic concentrations of MDA-MB-231 cells. Also, carnosol was found to …


Human 5’-Tailed Mirtrons Are Processed By Rnasep, Mohammad Farid Zia Oct 2021

Human 5’-Tailed Mirtrons Are Processed By Rnasep, Mohammad Farid Zia

Dissertations

Approximately a thousand microRNAs (miRNAs) are documented from human cells. A third appear to transit non-canonical pathways that typically bypass processing by Drosha, the dedicated nuclear miRNA producing enzyme. The largest class of non-canonical miRNAs are mirtrons which eschew Drosha to mature through spliceosome activity. While mirtrons are found in several configurations, the vast majority of human mirtron species are 5’-tailed. For these mirtrons, a 3’ splice site defines the 3’ end of their hairpin precursor while a “tail” of variable length separates the 5’ base of the hairpin from the nearest splice site. How this tail is removed is …


Reconstituting The Cyanobacterial Circadian Clock In Vitro, Pyong Hwa Kim May 2021

Reconstituting The Cyanobacterial Circadian Clock In Vitro, Pyong Hwa Kim

Dissertations

Cyanobacteria are photosynthetic organisms that are known to be responsible for oxygenating Earth’s early atmosphere. Having evolved to ensure optimal survival in the periodic light/dark cycle on this planet, their genetic codes are packed with various tools, including a sophisticated biological timekeeping system. Among the cyanobacteria is Synechococcus elongatus PCC 7942, the simplest clock-harboring organism with a powerful genetic tool that enabled the identification of its intricate timekeeping mechanism. The three central oscillator proteins—KaiA, KaiB, and KaiC—drive the 24 h cyclic gene expression rhythm of cyanobacteria, and the "ticking" of the oscillator can be reconstituted inside a test tube just …