Molecular Biology Commons^™

The Role Of Med13 In Proteaphagy, John Sauer, Brittany Friedson, Katrina Cooper

Rowan-Virtua Research Day

Regulation of proteasomes is important for adaptation to cellular stress. Previous studies have shown that following starvation stress, proteasomes are targeted for destruction by autophagy. However, how cells control proteasomes in response to nitrogen starvation remains unclear. This study delves into the intricate interplay between Med13, proteaphagy, and stress response regulation, aiming to elucidate their roles in cellular survival mechanisms. It focused on the highly conserved Cdk8 kinase module (CKM) of the Mediator complex a that plays a pivotal involvement in cellular signaling and gene regulation under stress conditions. During the investigation, we asked if the degradation of specific proteasome …

The Involvement Of Ubiquitin In Med13 Cyclin C Degradation Following Cellular Stress, Ayesha Gurnani, Brittany Friedson, Katrina Cooper

Rowan-Virtua Research Day

The Cdk8 Kinase Module is a dissociable regulator of cellular stress response genes, with degradation of its components Med13 and cyclin C eventually determining cell fate decisions such as engaging cell survival or cell death mechanisms. We aimed to explore the roles of ubiquitin in degradation of the Cdk8 Kinase Module following nitrogen starvation, with respect to the potential involvement of deubiquitinating enzyme Doa4, lysine linkage at position K63, and E2 ubiquitin conjugating enzymes Ubc4 and Ubc5. We utilized Western blot analysis to observe nitrogen starvation-induced degradation of Med13-HA in wild-type, doa4 mutant, and K63R yeast strains; degradation of cyclin …

Identifying Co-Factors That Drive Tra-1 Activator Function, Jibran Imtiaz, Youngquan Shen, Ronald Ellis

Rowan-Virtua Research Day

Gli proteins are involved in cell fate determination, proliferation, and patterning in many species and are major effectors of Hedgehog (Hh) signaling. There are three Gli proteins in humans, and mutations or errors in their regulation lead to a variety of developmental disorders or cancer. However, the mechanisms by which they interact with co-factors are poorly understood. We are analyzing co-factors of Gli proteins using TRA-1 in Caenorhabditis nematodes. The TRA-1 zinc fingers are structurally like those of other Gli proteins, and TRA-1 can be cleaved like other Gli proteins to form a repressor. However, its function has changed during …

Effect Of Uracil Dna Glycosylase Activity On The Efficacy Of Thymidylate Synthase Inhibitor/Hdac Inhibitor Combination Therapies In Colon Cancer, Rashmi Kulkarni, Brian P Weiser

Rowan-Virtua Research Day

Human uracil DNA glycosylase (UNG2) is responsible for removing uracil bases from DNA and initiates base excision repair pathways. Accumulation of uracil or its fluorinated analogs in DNA is one of the killing mechanisms of thymidylate synthase (TS) inhibitors in cancer cells, and depletion of UNG2 often enhances the toxicity of these anticancer drugs. We tested the effect of UNG2 KO on the efficacy of multiple TS inhibitors (5-fluorouracil, fluorodeoxyuridine, and pemetrexed) and we determined that, except for 5-fluorouracil, all other TS inhibitors were significantly more potent in UNG2 KO cells compared to wild-type HT29 cells. Interestingly, UNG2 protein levels …

Morphine-Induced Hyperactivity Is Attenuated By Intra-Accumbens Administration Of The Highly-Selective Dopamine D3 Receptor Antagonist Vk4-40, Mansi Patel, Desta M. Pulley, Daniel Manvich

Rowan-Virtua Research Day

Opioids exert their abuse-related effects by enhancing dopamine (DA) neurotransmission within the brain’s mesolimbic reward system, a neural projection involving DA neurons in the ventral tegmental area (VTA) that project to medium spiny neurons within the nucleus accumbens (NAc). Mu (MOR) are expressed by several populations of GABAergic neurons that tonically inhibit VTA DA neurons. By inhibiting these GABAergic neurons in a MOR-dependent manner, opioids indirectly enhance DA neurotransmission via disinhibition of DAergic neurons. Accumulating evidence indicates that selective pharmacological antagonism of the dopamine D3 receptor (D3R) attenuates the abuse-related effects of several opioids, but the neurobiological mechanisms mediating this …

Identification Of The E3 Ligase That Directs The Degradation Of Proteins That Control Cell Fate Decisions In Yeast, Prasanna Tati, Stephen D Willis, Katrina F. Cooper

Rowan-Virtua Research Day

The ubiquitin–proteasome system (UPS) and autophagy pathways are distinct, highly conserved proteolytic systems that play important roles in maintaining cellular homeostasis in response to environmental cues [1]. The goal of this project is to identify the E3 ligase that mediates the degradation of cyclin C following nitrogen starvation in yeast using quantitative Western blot analysis of cyclin C-myc following nitrogen starvation in mutants of known Ubc4/5 interacting E3 ligases. No potential E3 ligases were identified as stable after 4 hours of nitrogen starvation, suggesting redundancy in function.

Safety Of Silver Oxide Coated Biomaterials In Mice, Michael Klug, Darien L. Seidman, Rahyan Mahmoud, Destiny Morot, Lei Yu, Jeffrey D Hettinger, Renee M Demarest

Rowan-Virtua Research Day

It has been demonstrated that silver oxide coatings designed by our collaborators are able to prevent E. coli and P. aeruginosa attachment to biomaterials in vivo. These findings demonstrate that such coatings show promise in preventing the development of biofilm on biodevices. However, it is unknown if the use of silver oxide in this fashion is toxic in vivo. The goal of this project was to determine whether our silver oxide coatings are safe to use in vivo. To assess the toxicity of our silver oxide formula, mice were implanted with either silver oxide coated titanium discs or uncoated titanium …

Replication Protein A (Rpa) Targeting Of Uracil Dna Glycosylase (Ung2), Derek Chen, Brian P Weiser

Rowan-Virtua Research Day

Replication Protein A (RPA) is a single stranded DNA binding protein which stabilizes ssDNA for replication and repair. One function of RPA is to bind the DNA repair enzyme uracil DNA glycosylase (UNG2) and direct its activity towards ssDNA dsDNA junctions.

UNG2 removes uracil bases from DNA which can appear through dUMP misincorporation or through cytosine deamination. If uracil is present instead of a cytosine, then the original GC pair becomes a GU pair. The uracil will then base pair to adenine in the replicated daughter strand. This results in a GC → AT mutation that could contribute to cancer …

Substrate-Dependent Modulation Of Sirt2 By A Fluorescent Probe, 1-Aminoanthracene, David Bi, Prashit Parikh, Jie Yang, Brian P Weiser

Rowan-Virtua Research Day

Sirtuin isoform 2 (SIRT2) is an enzyme that catalyzes the removal of acyl groups from lysine residues. SIRT2’s catalytic domain has a hydrophobic tunnel where its substrate acyl groups bind. Here, we report that the fluorescent probe 1-aminoanthracene (AMA) binds within SIRT2’s hydrophobic tunnel in a substrate-dependent manner. AMA’s interaction with SIRT2 was characterized by its enhanced fluorescence upon protein binding (>10-fold). AMA interacted weakly with SIRT2 alone in solution (Kd = 37 μM). However, when SIRT2 was equilibrated with a decanoylated peptide substrate, AMA’s affinity for SIRT2 was enhanced ∼10-fold (Kd = 4μM). The peptide’s decanoyl chain and …

Evolutionary Conservation Of The Heterochronic Pathway In C. Elegans And C. Briggsae, Maria Ivanova, Eric G. Moss

Rowan-Virtua Research Day

Heterochronic genes control the sequence and timing of developmental events during four larval stages of Caenorhabitis nematodes. Mutations in these genes may cause skipping or reiteration of developmental events.

C. briggsae is a close relative of C. elegans. These species have similar morphology and share the same ecological niche. C. briggsae undergoes the same developmental pathway consisting of four larval stages before reaching adulthood. It also has the same set of heterochronic genes.

Lin-28 is one of the heterochronic genes that also exists in other animals from flies to humans. It conservatively blocks the maturation of let-7 miRNA, the process …