Biochemistry, Biophysics, and Structural Biology Commons^™

Three-Dimensional Chromatin Architecture Is Rapidly Restored After Dna Replication, Tyler K. Fenstermaker, Svetlana Petruk, Alexander Mazo

Department of Biochemistry and Molecular Biology Faculty Papers

Studies of post-replicative chromatin exclusively focus on the kinetics of protein binding after DNA replication to understand maintenance of transcriptional programs. Here we investigated both chromatin-bound factors and the three-dimensional architecture of the post-replicative genome in human cells. We found that transcription factors and chromatin looping proteins rapidly associate with nascent DNA. We discovered that the architectural factors, CTCF and YY1, bind to their target sequences immediately following DNA replication, and that chromatin loops from 39 to 425 kb re-form within 10 min of DNA replication. This suggests that the 3D structure of chromatin is at most briefly disrupted by …

Mitochondrial Dna Replication Is Regulated By Endoplasmic Reticulum-Mitochondrial Contact Sites, The Mitochondrial Calcium Uniporter, And Manganese, Amaia Lopez De Arbina, Angelica Zamudio-Ochoa, Mikel Muñoz-Oreja, Diego Perez-Rodriguez, Laura Mosqueira-Martín, Rebecca Lasalandra, Marina Villar-Fernandez, Uxoa Fernandez-Pelayo, Laura Rodriguez-Gomez, Seungtae Lee, Francisco Gil-Bea, Nerea Osinalde, Ainara Vallejo-Illaramendi, Dmitry Temiakov, Antonella Spinazzola, Ian Holt

Department of Biochemistry and Molecular Biology Faculty Papers

Mitochondrial DNA replication occurs at contact sites between the endoplasmic reticulum (ER) and mitochondria (ERMCS). Beyond the known role of the tubular ER protein RTN4, the factors regulating this process are poorly defined. Here, we show that repressing the ER protein ERLIN2 in human fibroblasts depletes ER-mitochondrial contact sites and inhibits mitochondrial DNA replication, as does silencing RTN4 or the ER-mitochondrial tether GRP75. GRP75 or RTN4 scarcity also decreases the level of the mitochondrial calcium uniporter (MCU), whose inhibition blocks mitochondrial DNA synthesis. Because ERMCS depletion did not diminish mitochondrial calcium, and MCU complex can transport manganese, we tested whether …

Role Of Cellular Proteins In The Regulation Of Herpes Simplex Virus Type 1 Gene Expression And Dna Replication, Joseph R. Heath

Electronic Theses and Dissertations

Herpes simplex virus type 1 (HSV-1) is a ubiquitous human pathogen that infects the majority of the human population. To facilitate infection, this virus relies on a combination of host and viral factors. Previous studies have revealed a number of host proteins that associate with the HSV-1 genome throughout infection but their putative role(s) in this process remain undefined. This study aims to examine two such proteins to determine their contributions to HSV-1 gene expression and DNA replication. The first of these factors is Ints3, a subunit of the Integrator complex. This protein complex functions in transcription regulation, and Ints3 …

The Role Of The Cdk8 Kinase Module In Maintaining Proteostasis, Stephen Willis

Theses and Dissertations

The underlying etiology of numerous disease states results from perturbations in the maintenance of cellular proteostasis. Carcinogenesis relies on these perturbations to foster uncontrolled cell growth and eventual metastases, while neurodegenerative diseases are a consequence of such perturbations. Control of these processes occurs at numerous molecular levels, commonly starting with transcription. A key transcriptional complex that is involved is the CDK8 Kinase Module (CKM). The CKM is conserved from yeast to man, forming a tetrameric complex consisting of MED12, MED13, CDK8, and CCNC. The CKM has not only been implicated in a variety of cancers but also in a spectrum …

Modeling Nonsegmented Negative-Strand Rna Virus (Nnsv) Transcription With Ejective Polymerase Collisions And Biased Diffusion, Felipe-Andres Piedra

Research Symposium

Background: The textbook model of NNSV transcription predicts a gene expression gradient. However, multiple studies show non-gradient gene expression patterns or data inconsistent with a simple gradient. Regarding the latter, several studies show a dramatic decrease in gene expression over the last two genes of the respiratory syncytial virus (RSV) genome (a highly studied NNSV). The textbook model cannot explain these phenomena.

Methods: Computational models of RSV and vesicular stomatitis virus (VSV – another highly studied NNSV) transcription were written in the Python programming language using the Scientific Python Development Environment. The model code is freely available on GitHub: …

Multiphasic Molecular Mechanisms Regulate Expression Of Interleukin 1Β, As Well As Other Immediate-Early Genes, In Monocytes And Macrophages, David Macar

Electronic Theses and Dissertations

Interleukin 1β (IL-1β), an important cytokine in both health and disease, functions as a major proinflammatory mediator of pathological challenges, including involvement in the cytokine storm associated with Macrophage Activation Syndrome, Hemophagocytic Lymphohistiocytosis and the severe secondary effects of SARS-CoV-2 infection. Therapeutic approaches to limiting the effects of IL-1β protein have focused either on specific protein neutralization before release from activated macrophages (by general metabolic inhibitors and inflammasome inhibition) or after release by ligand and receptor obstruction (e.g., Canakinumab, Anakinra and Rilonacept). Although these approaches are efficacious, they inhibit steps after gene expression. Since a single gene expresses …

Elucidating The Direct Role Of M6a In The Human Transcriptome, Lana Al Hasani

Dissertations and Theses (Open Access)

The best characterized and most abundant internal RNA modification is the methylation of adenosine at position 6 to give N6-methyladenosine (m6A). m6A modification on cellular RNAs was discovered in the 1970s. The past decade has witnessed major progress that illustrated important roles of this mark in various aspects of gene control. Due to its pleiotropic roles, the direct effect of m6A regulation of gene expression has remained incompletely understood. Traditional methods of understanding protein function, like CRISPR/Cas9 and RNA interference, have many limitations and have halted the process of fully understanding the direct functions of m6A. Here, we attempt alternative …

Characterizing The Dynamic Localization Of Cmi In Early Drosophila Development, Asra Habibullah

Master's Theses

The COMPASS-like family of lysine methyltransferases, MLR/MLX complexes, are epigenetic regulators that are essential for normal development through the methylation of the fourth lysine residue on histone 3 (H3K4), a universal epigenetic mark associated with active transcription. This family of complexes is highly conserved from yeast to mammals and the genes encoding the human MLR complexes have been associated with various developmental diseases and cancers (Dingwall and Fagan, 2019). In D. melanogaster, the enzymatic methyltransferase core of this complex is composed of two proteins: Cara Mitad (Cmi, also known as Lpt) and Trithorax-related (Trr). Although these proteins have been shown …

Transcriptional Mechanisms Of Neuroprotection In Excitotoxicity Driven Neurodegeneration In C. Elegans, Zelda Z. Mendelowitz

Dissertations, Theses, and Capstone Projects

Excitotoxicity is notorious for triggering neuronal cell death in both developmental and adult-onset neurodegenerative diseases. In excitotoxicity, excessive concentrations of Glutamate in the synapse overstimulate Glutamate Receptors (GluRs) on postsynaptic neurons. While GluR mediated degenerative mechanisms remain obscure, GluR activation was surprisingly found to also have a neuroprotective effect through activation of specific transcriptional programs. To identify evolutionarily conserved transcriptional programs in neuroprotection we use a C. elegans model of excitotoxic necrosis (glt-3;nuIs5). We have identified that non-canonical activation of the transcription factor CRH-1/CREB mediates neuroprotection in our excitotoxicity model. We found the Histone Acetyl Transferase, MYS-1/KAT6, and the neuronal …

Determining The Roles Of The Oligomerization And C-Terminal Domains In Mutant P53 Gain-Of-Function Activities, George K. Annor

Dissertations, Theses, and Capstone Projects

The tumor suppressor p53 (TP53) gene is often mutated in cancer, with missense mutations found in the central DNA binding domain, and less often in the oligomerization domain (OD) and C-terminal domain (CTD). The OD and CTD have been found to be critical for the tumor suppressor functionality of wild-type p53 (wtp53). Specific missense mutations in the DNA binding domain have been found to confer new gain-of-function (GOF) activities. Mutations that destabilize tetramer formation, or deletion of key lysine residues within the CTD, downregulate the ability of wtp53 to transactivate (increase the rate of transcription of) its target …

Ewing Sarcoma Transcriptome: Identification Of Foxn3 As A Novel Target Of Ews-Fli1, Natasha Kreiling

Theses & Dissertations

Ewing Sarcoma is an aggressive cancer characterized by a fusion gene formed from a chromosomal translocation between a RNA binding protein and a transcription factor. The most common fusion gene is EWS-FLI1 a potent oncogenic transcription factor responsible for initiating genome instability. EWS-FLI1 promotes tumor growth by dysregulating several genes and pathways. We have identified FOXN3, an important gene in cell cycle control and development, as being suppressed by EWS-FLI1. In the future, a better understanding of FOXN3 and its ability to act as a tumor suppressor in EWS will unravel novel mechanisms of EWS pathogenesis, potential biomarker and drug …

Generating A Colorimetric Ssa4 Transcript Export Reporter For Multicopy Suppression Screen In S. Cerevisiae, Zaid Hatem

[Archive] Belmont University Research Symposium (BURS)

The export of mRNA from the nucleus to the cytoplasm is a regulatory point that is essential to the pathway of gene expression in eukaryotic cells. The export of mRNA transcripts is mediated through selective doorways called the nuclear pore complexes (NPC). Additionally, there are proteins associated with the nuclear pore complex that assist in facilitating the export. This includes association with the export receptor, Mex67, which binds to the transcript and ferries it through NPCs. During cellular stress, such as heat shock, the export of housekeeping mRNA transcripts is halted, forcing these transcripts to remain inside the nucleus and …

Establishing A Biochemical System For The Purification And Atpase Activity Of Gst-Dbp5, Sarah R. Utley, Rachel E. Rigsby Phd, Rebecca L. Adams Phd

Science University Research Symposium (SURS)

The export of mRNA out of the nucleus is a crucial step for eukaryotic gene expression. The export of mRNA transcripts is aided by Mex67, which allows export through the nuclear pore complex doorways in the nuclear envelope. Once out of the nucleus, a protein known as Dbp5, bound to ATP, Gle1, and Nup42 aids in the directionality of mRNA export by helping remove Mex67 from the mRNA strand. Following interaction with RNA, Dbp5 then hydrolyzes ATP so that it unbinds the mRNA, allowing for enzyme recycling. Previous efforts worked towards the purification of Dbp5, but the attempts were unsuccessful …

The 4d Living Genome, Julianna Arlene Sherman Goelzer

Boise State University Theses and Dissertations

Over the last few decades great advances have been made in our understanding of gene expression and the human genome. In 2003 the human genome was sequenced for the first time, allowing us to discover its true importance in human health. While sequencing the human genome was a great advance, it ultimately created more questions than it answered. It is known that the genomic sequence is extremely important in genome regulation, however recent studies have shown that the 4D (spatiotemporal) organization and dynamics of the living genome plays an equally critical role in regulation of gene expression. A key factor …

Cyclin C Determines Cell Fate In Response To Oxidative Stress And Proteasome Inhibition, David C. Stieg

Graduate School of Biomedical Sciences Theses and Dissertations

In response to various sources of cellular stress, the coordination of intracellular events is necessary to elicit the appropriate molecular response. In particular, the reprogramming of gene expression by stress-specific transcription factors drives the activation of signaling pathways, triggering either cell survival or regulated cell death pathways. The Cdk8 kinase module (CKM) is a highly conserved transcriptional regulatory complex with a role in this decision. The CKM is composed of Cdk8, its activating partner cyclin C, and two scaffold proteins, Med12 and Med13. The CKM is a detachable subunit of the Mediator complex, which interacts with RNA polymerase II to …

Global Coordination Between Gene Expression Processes In C. Crescentus, James Raymond Aretakis

Wayne State University Dissertations

Gene expression is an essential process of all organisms which occurs in two steps, mRNA transcription, and translation and which is shut off by mRNA decay. For a bacterium to grow and divide, these steps need to be tuned to optimize the synthesis rates of thousands of proteins from their genes. Genome-wide experiments were used to determine the absolute transcription rates, mRNA degradation rates, and translation rates on a gene by gene basis in the model bacterium Caulobacter crescentus. This not only provides a system biology view of the organism’s gene expression resource allocation, but also provides a chance to …

P53 Drives A Transcriptional Program That Elicits A Non-Cell-Autonomous Response And Alters Cell State In Vivo, Sydney Moyer

Dissertations and Theses (Open Access)

Cell stress and DNA damage activate the tumor suppressor p53, triggering transcriptional activation of a myriad of target genes. The molecular, morphological, and physiological consequences of this activation remain poorly understood in vivo. We activated a p53 transcriptional program in mice by deletion of Mdm2, a gene which encodes the major p53 inhibitor. By overlaying tissue-specific RNA-sequencing data from pancreas, small intestine, ovary, kidney, and heart with existing p53 ChIP-sequencing, we identified a large repertoire of tissue-specific p53 genes and a common p53 transcriptional signature of seven genes which included Mdm2 but not p21. Global p53 activation …

New Mechanisms That Regulate Dna Double-Strand Break-Induced Gene Silencing And Genome Integrity, Dante Francis Deascanis

USF Tampa Graduate Theses and Dissertations

Proliferating cells are constantly threatened by genotoxic stressors that can potentially lead to genomic instability. Breaks in the DNA, namely double-strand breaks, are detrimental sources of damage that must be repaired to maintain genomic integrity and prevent potential tumorigenesis. Here we discuss a gene silencing mechanism flanking damaged chromatin. Gene silencing and transcriptional repression at damaged DNA are necessary to prevent potential genomic aberrations from occurring through conflicts with the DNA repair machinery. BMI1, a core polycomb protein in the polycomb repressive complex 1 (PRC1) has been known to play a role in gene silencing at damaged chromatin. However, the …

Calcineurin, Trevor P. Creamer

Molecular and Cellular Biochemistry Faculty Publications

The serine/threonine phosphatase calcineurin acts as a crucial connection between calcium signaling the phosphorylation states of numerous important substrates. These substrates include, but are not limited to, transcription factors, receptors and channels, proteins associated with mitochondria, and proteins associated with microtubules. Calcineurin is activated by increases in intracellular calcium concentrations, a process that requires the calcium sensing protein calmodulin binding to an intrinsically disordered regulatory domain in the phosphatase. Despite having been studied for around four decades, the activation of calcineurin is not fully understood. This review largely focuses on what is known about the activation process and highlights aspects …

Changes In Gene Expression Profiles In Müller Glia Following Exposure To An Α7 Nicotinic Acetylcholine Receptor Agonist, Megan L. Stanchfield

Masters Theses

Previous studies from this lab have determined that dedifferentiation of Müller glia (MG) occurs after application of an α7 nicotinic acetylcholine receptor agonist, PNU-282987 (PNU), to retinal pigment epithelial (RPE) cells in adult rodents. This study was designed to explore the role of the HB-EGF/Ascl1/Lin28a signaling pathway in MG dedifferentiation to retinal progenitor cells. RNAseq was performed on MG following contact with RPE-J cells treated with PNU-282987. Up- or down-regulated genes were compared with published literature of MG dedifferentiation that occurs in lower vertebrate regeneration or with transcript profiles during early mammalian development. Between 8-12 hours, up-regulation was observed in …

Genome Maintenance Roles Of Polycomb Transcriptional Repressors Bmi1 And Rnf2, Anthony Richard Sanchez Iv

USF Tampa Graduate Theses and Dissertations

The coordination of transcription, replication, and DNA damage response (DDR) is vital for maintaining normal cellular homeostasis. All of these processes take place on the chromatin and thus, the temporal and spatial separation of the factors responsible are necessary for each to be correctly completed. Here we detail several novel processes contributing to this network.

BMI1 is a component of the Polycomb Repressive Complex 1 (PRC1) which plays a key role in maintaining epigenetic silencing programs during development. Recently, BMI1 and other members of PRC1 like RNF2 have been implicated gene silencing during the DDR; however, the mechanism through which …

Probing The Limits Of Singular Gene Expression Through The Activity Of High Representation Odorant Receptor Transgenes, Eugene Lempert

Dissertations, Theses, and Capstone Projects

Singular gene expression is a common phenomenon in biology, making its appearance in immunoglobulin selection, protocadherin expression, X chromosome-inactivation, random monoallelic expression, and olfactory receptor choice. Singularity involves an activation and a feedback step. The mechanisms of singular gene choice have some capacity to integrate additional member genes while still maintaining singularity, but will activate an additional member if an earlier choice was incapable of triggering the feedback step. Odorant Receptor (OR) genes are substantially divergent from each other in terms of coding sequence, promoter structure, and genomic locus, all of which plays a role in how many Olfactory Sensory …

Investigating The Redox Sensitivity Of Mitf Splice Variants, Rachel Berryman

Senior Theses

Within pigment-producing cells known as melanocytes, the transcription factor MITF is intimately involved in regulating genes associated with cell cycle maintenance and melanocyte differentiation. Research, however, has provided conflicting results on the relationship between the expression levels of MITF and melanocyte cell fate. To complicate matters, two splice variants of MITF exist, differing by only 18 base pairs. These variants have been observed at variable levels of expression in melanocyte and melanoma cells, raising the question as to their functional purpose. Building upon previous research by the Leachman/Cassidy lab that identified the redox sensitivity of MITF while additionally establishing a …

Characterization Of Drosophila Boundary Element Associated Factor Beaf-32b Interactions With Transcription Factors And Chromatin Remodeling Complexes., Yuankai Dong

LSU Doctoral Dissertations

BEAF (Boundary Element-Associated Factor) was originally identified as a chromatin domain insulator binding protein, suggesting that it might play a role in linking gene regulation to chromatin organization and dynamics. Genome-wide mapping found that BEAF is usually found near transcription start sites, often of housekeeping genes, suggesting that it might play a role in promoter function. This would be a nontraditional role for an insulator binding protein. To gain insight into molecular mechanisms of BEAF function, we identified proteins that interact with BEAF using yeast 2-hybrid assays. Here we focus on three identified transcription factors: Bcd, Scr and Sry-δ. Interactions …

Launching The Next Generation : Transcriptional Regulation During Oogenesis, Alicia K. Mccarthy

Legacy Theses & Dissertations (2009 - 2024)

Germ cells give rise to gametes and link generations by passing genetic information from parent to offspring. Gametes arise from, in many sexually reproducing organisms, germline stem cells (GSCs) which are set aside early during development. GSCs have an amazing capacity to undergo self-renewal to give rise to a pool of undifferentiated cells, while also differentiating to generate specialized germ cells such as haploid gametes. Upon female GSC differentiation, mitotically dividing germ cells can initiate meiosis, and mature within a follicle. During maturation, the specified oocyte is provided with a trust fund of RNAs and proteins for the next generation …

Termination-Independent Role Of Rat1 In Cotranscriptional Splicing In Budding Yeast, Zuzer Hakimuddin Dhoondia

Wayne State University Dissertations

Rat1 is a 5′→3′ exoribonuclease in budding yeast belonging to the XRN-family of nucleases. It is a highly conserved protein with homologs being present in fission yeast, flies, worms, mice and humans. Rat1 and its homolog in metazoan have been shown to function in multiple facets of RNA metabolism. In this study, we report a novel role of Rat1 in splicing of pre-mRNA in budding yeast. In the absence of the functional Rat1 in the nucleus, an increase in the level of unspliced transcripts was observed in yeast cells. Strand-specific TRO analysis revealed that the accumulation of unspliced transcripts upon …

Characterization Of The Dyrk1a Protein-Protein Interaction Network, Varsha Ananthapadmanabhan

Theses and Dissertations

Human Dual specificity tyrosine (Y)-Regulated Kinase 1A (DYRK1A) is a protein kinase encoded by a dosage-dependent gene. An extra copy of DYRK1A contributes to Down syndrome (DS) pathogenesis while loss of one allele causes severe mental retardation and autism. DYRK1A is involved in phosphorylation of several proteins that regulate cell cycle control and tumor suppression. However, the function and regulation of this kinase is not well understood and current knowledge does not fully explain dosage-dependent function of this important kinase. Our previous proteomic studies identified several novel DYRK1A interacting proteins including RNF169, FAM117B, TROAP, LZTS1, LZTS2 and DCAF7. In this …

Dissecting The Roles Of Human Smc Complexes In Transcription Regulation And Chromatin Organization, Ruoyu Wang

Dissertations and Theses (Open Access)

Metazoans utilize a constellation of distal regulatory elements to control gene transcription, and therefore they have to forge highly complex chromatin loops to spatially bridge these regulatory elements and genes in the three-dimensional (3D) genome. However, the hierarchy of chromatin contacts and their underlying mechanisms are not well-understood. SMC complexes including Cohesin complex and Condensin complex has been widely proposed to organize 3D genome structure, and further regulate metazoans’ gene transcription. Here, we aim to dissect the direct functions of SMC complexes (both Cohesin and Condensin) in transcriptional regulation and 3D genome organization, by utilizing an inducible protein degradation system. …

Divergent Transcriptional Regulation Of Suppressors Of Cytokine Signaling Genes In Adipocytes, Paula Mota De Sa

LSU Doctoral Dissertations

The Janus Kinase - Signal Transducer and Activator of Transcription (JAK-STAT) signaling pathway transduces several signals crucial for development and homeostasis. Suppressors of cytokine signaling (SOCS) proteins control JAK-STAT signaling via a negative feedback loop. The transcription factor STAT5 is known to play a significant role in fat cell development and function, and several studies suggest that acetylation may affect STAT5 transcriptional activity. To test this hypothesis, we treated 3T3-L1 adipocytes with growth hormone (GH) to activate STAT5 in the presence or absence of histone deacetylase (HDAC) inhibitors. STAT5 acetylation levels were low in adipocytes and mostly unchanged by the …

Transcriptional Regulation Of Dksa In E. Coli, Daniel Thomas Woods

Legacy Theses & Dissertations (2009 - 2024)

DksA is a global transcription factor that binds RNAP directly to regulate the expression of many genes and operons, including ribosomal RNA, in a ppGpp-dependent or ppGpp–independent manner. It is also involved in facilitating the process of DNA replication by removing stalled transcription elongation complexes that could block the progress of the replication fork. In addition, DksA is important for colonization, establishment of biofilms, and pathogenesis. In order to sustain these various functions, an adequate level of cellular DksA is required. This work tested the hypothesis that the E. coli dksA is substantially regulated at the level of transcription. Using …