Cell Biology Commons^™

Meiosis In Budding Yeast, G. Valentin Borner, Andreas Hochwagen, Amy J. Macqueen

Biological, Geological, and Environmental Faculty Publications

Meiosis is a specialized cell division program that is essential for sexual reproduction. The two meiotic divisions reduce chromosome number by half, typically generating haploid genomes that are packaged into gametes. To achieve this ploidy reduction, meiosis relies on highly unusual chromosomal processes including the pairing of homologous chromosomes, assembly of the synaptonemal complex, programmed formation of DNA breaks followed by their processing into crossovers, and the segregation of homologous chromosomes during the first meiotic division. These processes are embedded in a carefully orchestrated cell differentiation program with multiple interdependencies between DNA metabolism, chromosome morphogenesis, and waves of gene expression …

Dynamics And Inhibition Of Abc And Rnd Transporters Associated With Multidrug Resistances In Cancer And Pathogenic Bacteria, Hang Zhao

Biological Sciences Theses and Dissertations

The overexpression of efflux transporters is deemed to be one of the important mechanisms that contribute to Multidrug Resistance (MDR). In this dissertation, three transporters of significance were studied, the Breast Cancer Resistance Protein (BCRP/ABCG2) in a variety of cancer cells, the mtrCDE transporter from Neisseria gonorrhoeae, and the acrAB-tolC transporter from Escherichia coli. It is well known that the overexpression of BCRP in cancer cells results in these cells being resistant to the effects of many chemotherapeutics. This results in multidrug resistance for this cancer because of the fact that BCRP can transport many different types of …

Using Crispr To Generate Integrated Ssa4-Gfp Reporter Strains, Emma Norman, Rebecca Adams

Science University Research Symposium (SURS)

Using CRISPR to Generate Integrated Ssa4-GFP Reporter Strains

Emma Norman, Rebecca Adams, PhD

Proteins play critical roles in numerous cellular processes. In order to synthesize these important molecules in eukaryotes, DNA is first transcribed into an intermediate molecule, mRNA, in the nucleus. The export of mRNA from its origin in the nucleus to the site of protein production, the cytoplasm, is an integral step in protein synthesis. When a cell is subjected to stress, such as heat shock, most mRNA export is halted, as export proteins are inactivated, and cellular machinery is redirected towards recovery. However, particular transcripts, including the …

Structural Insights Into The Cl-Par-4 Protein: Ionic Requirements, Conformational Transitions, And Interaction With Cisplatin, Krishna Kumar Raut

Chemistry & Biochemistry Theses & Dissertations

Cancer continues to be the leading global cause of death, with challenges in early diagnosis, drug resistance, non-specific drug targeting, and cancer recurrence and metastasis posing formidable obstacles in cancer therapy. In this context, Prostate Apoptosis Response-4 (Par-4), a pro-apoptotic tumor suppressor protein, emerged as a promising therapeutic target due to its ability to selectively induce apoptosis in cancer cells, thereby minimizing the drug-associated adverse effects. However, a comprehensive understanding of the structural features of Par-4, specifically the caspase-cleaved fragment (cl-Par-4), is crucial for therapeutic advancements.

This dissertation investigated the effects of various ions, both monovalent and divalent, on the …

Modified Vaccine Vectors To Understand Adjuvant Functions Of Listeria During Chronic Schistosomiasis, Stephanie K. Norwood

Biological Sciences Theses & Dissertations

Vaccination is one of the most effective strategies employed to prevent infectious diseases. Successful vaccination is dependent upon the induction of a specific, robust, and prolonged immune response. One of the major challenges faced by vaccine development is vaccine failure due to host-related factors that can modulate the immune system, which leads to non-responsiveness to vaccinations. The generation of new vaccine strategies is imperative to combat these effects. Live bacterial vectors are one approach used as they can elicit humoral immunity, cellular immunity, or both. Listeria monocytogenes is a Gram positive, intracellular pathogen that is an effective bacterial vaccine vector …

Pulsed Electric Field Ablation: Mechanisms Of Differential Cell Sensitivity And Methods To Mitigate Neuromuscular Excitation, Emily Gudvangen

Biomedical Engineering Theses & Dissertations

Ablation therapies aim to destroy tumors while maintaining minimal damage to surrounding healthy tissue. Pulsed electric field (PEF) ablation targets the cell membrane during the destruction of tissues, which consequently spares extracellular structures such as ducts and blood vessels, leaving the framework for tissue regeneration. However, the utility of PEF is limited by neuromuscular excitation, causing pain and involuntary muscle contraction. To identify PEF protocols that efficiently ablate tissue while minimizing neuromuscular stimulation, various PEF protocols differing in pulse duration, shape, and repetition rate were tested. The ratio of cell death and nerve excitation thresholds, which determines the range of …

Distinct Camp Signaling Microdomains Differentially Regulate Melanosomal Ph And Pigmentation, Maftuna Yusupova, Dalee Zhou, Jaewon You, Jeydi Gonzalez-Guzman, Megha B. Ghanta, Hong Pu, Zalfa Abdel-Malek, Qiuying Chen, Steven S. Gross, John August D'Orazio, Shosuke Ito, Kazumasa Wakamatsu, Melissa L. Harris, Jonathan H. Zippin

Markey Cancer Center Faculty Publications

cAMP signaling is a well-established regulator of melanin synthesis. Two distinct cAMP signaling pathways—the transmembrane adenylyl cyclase pathway, activated primarily by the MC1R, and the soluble adenylyl cyclase (sAC) pathway—affect melanin synthesis. The sAC pathway affects melanin synthesis by regulating melanosomal pH, and the MC1R pathway affects melanin synthesis by regulating gene expression and post-translational modifications. However, whether MC1R genotype affects melanosomal pH is poorly understood. We now report that loss of function MC1R does not affect melanosomal pH. Thus, sAC signaling appears to be the only cAMP signaling pathway that regulates melanosomal pH. We also addressed whether MC1R genotype …

Inhibition Of Mitochondrial Fission Activates Glycogen Synthesis To Support Cell Survival In Colon Cancer, Sumati Raj Hasani, Lyndsay E. A. Young, Warren Van Nort, Moumita Banerjee, Dylan R. Rivas, Jinhwan Kim, Xiaopeng Xiong, Ramon C. Sun, Matthew S. Gentry, Hiromi Sesaki, Tianyan Gao

Markey Cancer Center Faculty Publications

Metabolic reprogramming has been recognized as one of the major mechanisms that fuel tumor initiation and progression. Our previous studies demonstrate that activation of Drp1 promotes fatty acid oxidation and downstream Wnt signaling. Here we investigate the role of Drp1 in regulating glycogen metabolism in colon cancer. Knockdown of Drp1 decreases mitochondrial respiration without increasing glycolysis. Analysis of cellular metabolites reveals that the levels of glucose-6-phosphate, a precursor for glycogenesis, are significantly elevated whereas pyruvate and other TCA cycle metabolites remain unchanged in Drp1 knockdown cells. Additionally, silencing Drp1 activates AMPK to stimulate the expression glycogen synthase 1 (GYS1) mRNA …

Phosphatidic Acid Binding To Patched Contributes To The Inhibition Of Smoothened And Hedgehog Signaling In Drosophila Wing Development, Jie Zhang, Yajuan Liu, Chi Wang, Craig W. Vander Kooi, Jianhang Jia

Markey Cancer Center Faculty Publications

Hedgehog (Hh) signaling controls growth and patterning during embryonic development and homeostasis in adult tissues. Hh binding to the receptor Patched (Ptc) elicits intracellular signaling by relieving Ptc-mediated inhibition of the transmembrane protein Smoothened (Smo). We uncovered a role for the lipid phosphatidic acid (PA) in the regulation of the Hh pathway in Drosophila melanogaster. Deleting the Ptc C-terminal tail or mutating the predicted PA-binding sites within it prevented Ptc from inhibiting Smo in wing discs and in cultured cells. The C-terminal tail of Ptc directly interacted with PA in vitro, an association that was reduced by Hh, and increased …

Regulated Translocation Of Neutral Sphingomyelinase-2 To The Plasma Membrane Drives Insulin Resistance In Steatotic Hepatocytes, Salim S. El-Amouri, Alexander A. Karakashian, Erhard Bieberich, Mariana N. Nikolova‑Karakashian

Markey Cancer Center Faculty Publications

Abstract Obesity-associated diabetes is linked to the accumulation of ceramide in various organs, including the liver. The exact mechanisms by which ceramide contributes to diabetic pathology are unclear, but one proposed scenario is that ceramide accumulation may inhibit insulin signaling pathways. It is unknown however whether the excess ceramide is generated proximal to the insulin receptor, that is, at the plasma membrane (PM), where it could affect the insulin signaling pathway directly, or the onset of insulin resistance is due to ceramide- induced mitochondrial dysfunction and/or lipotoxicity. Using hepatic cell lines and primary cultures, gain- and loss- of function approach, …

Stat3 Modulates Cd4+ T Mitochondrial Dynamics And Function In Aging, Emelia Zukowski, Marco Sannella, Jack Donato Rockhold, Gabriella Kalantar, Jingting Yu, Sara Santacruz-Calvo, Madison K. Kuhn, Nasun Hah, Ling Ouyang, Tzu-Wen Wang, Lyanne Murphy, Heather Marszalkowski, Kaleigh Gibney, Micah J. Drummond, Elizabeth A. Proctor, Hatice Hasturk, Barbara S. Nikolajczyk, Leena P. Bharath

Markey Cancer Center Faculty Publications

Aging promotes numerous intracellular changes in T cells that impact their effector function. Our data show that aging promotes an increase in the localization of STAT3 to the mitochondria (mitoSTAT3), which promotes changes in mitochondrial dynamics and function and T-cell cytokine production. Mechanistically, mitoSTAT3 increased the activity of aging T-cell mitochondria by increasing complex II. Limiting mitoSTAT3 using a mitochondria-targeted STAT3 inhibitor, Mtcur-1 lowered complex II activity, prevented age-induced changes in mitochondrial dynamics and function, and reduced Th17 inflammation. Exogenous expression of a constitutively phosphorylated form of STAT3 in T cells from young adults mimicked changes in mitochondrial dynamics and …

Early Development Of C3ar1-Targeting Chimeric Antigen Receptor T Cells For The Treatment Of Glioblastoma Multiforme, Cameron Fraser

Electronic Theses, Projects, and Dissertations

Glioblastoma multiforme is the most aggressive type of glioma, demonstrating extremely low long-term survival despite modern therapies. Chimeric antigen receptor T cells have shown extreme levels of success in the treatment of B cell lymphomas through persistent anti-tumor activity. Prior research has demonstrated the therapeutic potential in targeting the C3a-C3aR1 pathway as it acts in an autocrine loop, maintaining the proliferation and survival of cancer stem cells within the tumor. Here, we reorient the treatment to target C3aR1 for the treatment of glioblastoma multiforme. In order to achieve this, Jurkat immortalized T cells will express various chimeric antigen receptor designs …

Integrating Clinical Cancer And Ptm Proteomics Data Identifies A Mechanism Of Ack1 Kinase Activation, Eranga R. Balasooriya, Deshan Madhusanka, Tania P. López-Palacios, Riley J. Eastmond, Dasun Jayatunge, Jake J. Owen, Jack S. Gashler, Christina M. Egbert, Chanaka Bulathsinghalage, Lu Liu, Stephen R. Piccolo, Joshua L. Andersen

Faculty Publications

Beyond the most common oncogenes activated by mutation (mut-drivers), there likely exists a variety of low-frequency mut-drivers, each of which is a possible frontier for targeted therapy. To identify new and understudied mut-drivers, we developed a machine learning (ML) model that integrates curated clinical cancer data and posttranslational modification (PTM) proteomics databases. We applied the approach to 62,746 patient cancers spanning 84 cancer types and predicted 3,964 oncogenic mutations across 1,148 genes, many of which disrupt PTMs of known and unknown function. The list of putative mut-drivers includes established drivers and others with poorly understood roles in cancer. This ML …

Potent Bile Acid Microbial Metabolites Modulate Clostridium Perfringens Virulence, Tahrir Jatli Alenezi, Ying Fu, Bilal Alrubaye, Thamer Alanazi, Ayidh Almansour, Hong Wang, Xiaolun Sun

Poultry Science Faculty Publications and Presentations

Clostridium perfringens is a versatile pathogen, inducing diseases in the skin, intestine (such as chicken necrotic enteritis (NE)), and other organs. The classical sign of NE is the foul smell gas in the ballooned small intestine. We hypothesized that deoxycholic acid (DCA) reduced NE by inhibiting C. perfringens virulence signaling pathways. To evaluate the hypothesis, C. perfringens strains CP1 and wild-type (WT) HN13 and its mutants were cultured with different bile acids, including DCA and isoallolithocholic acid (isoalloLCA). Growth, hydrogen sulfide (H₂S) production, and virulence gene expression were measured. Notably, isoalloLCA was more potent in reducing growth, H …

Stem Cell Technology For Age Related Macular Degeneration Intervention, Laura Valdez

Research Symposium

Retinal pigmented epithelium (RPE) cells are located between the choroid and photoreceptors within the eye and are essential to provide nutrients from blood to rods and cones, as well retinoids of the visual cycle. Vision loss and various ocular diseases are attributable to the degeneration or dysfunction of the RPE cells, leading to blindness.One of the major ocular problem from RPE dysfunction is macular degeneration. Age-related macular degeneration (AMD) can be frequently diagnosed in patients over the age of 60. In the early stages of AMD, some symptoms may not be noticeable but will lead to vision loss in both …

Natural Remedies To Combat Aberrant Hallmark Signatures Including Altered Glycosylation In Oral Carcinoma, Kruti A. Mehta, Jayendra B. Patel, Prabhudas S. Patel

Research Symposium

Background: Tobacco associated oral cancers remain a major concern in India with higher incidence and mortality making it an Indian-centric burning issue. To combat this dreadful disease, we investigated effects of certain natural compounds on the hallmark signatures including glycosylation transcripts levels in oral carcinoma.

Methods: The tongue carcinoma cells- SAS cells were treated with tobacco compounds, natural compounds and Cisplatin. RNA was isolated from the cells and converted to cDNA. RT-qPCR was performed to evaluate expression levels of various genes.

Results: The treatment of tobacco compounds resulted in similar pattern of altered makers (ST3GAL1, NEU3, FUT5, FUT6, MMP2, BCL2) …

International Conference On Cancer Health Disparities, Juhi Rais, Asif Jafri, Neelam Shivnath, Habiba Khan, Md Arshad

Research Symposium

Background: Biochanin A, an isoflavone that is mainly present in red clover, has potent chemopreventive properties against many cancers. Ovarian carcinoma is fifth most common and deadliest gynaecological malignancy that causes the highest mortality in females worldwide. Hence a substantial need for new therapies for combating this gynaecological malignancy arises.

Methods: The present study aimed to investigate anti-cancerous potentials of biochanin A on cultured human ovarian carcinoma PA-1 cells through the cell viability assay, cellular apoptosis, disruption of mitochondrial membrane potential (MMP), involvement of ROS, cell cycle kinetics, and expression of apoptosis-related genes namely, p53, Bax, Bcl-2, Noxa and Puma. …

Immunepotent Crp Enhances Cyclophosphamide-Induced Cytotoxicity Through A Caspase Independent But Ros Dependent Mechanism In Triple Negative-Breast Cancer Cells, Ana L. Rivera, A. C. Martínez-Torres, C. Rodríguez-Padilla

Research Symposium

Background: Breast cancer (BC) is one of the leading causes of cancer death worldwide. Cyclophosphamide (CYP) remains a mainstay in cancer therapy mainly in the triple negative breast cancer subtype (TNBC) in spite of harmful adverse effects and cell death-resistances. To face this, combination of chemotherapies and immunotherapies has been proposed. IMMUNEPOTENT CRP (ICRP) is an immunotherapy that has cytotoxic effects in several cancer cells without affecting peripheral blood mononuclear cells (PBMC) and CD3+ cells, beside improving clinical parameters of chemotherapy-treated patients. The aim of this study was to evaluate the mechanism of cytotoxicity induced by ICRP in combination with …

Engineered Exosomes For The Multimodal Imaging Directed Photo-Immunotherapy Of Colorectal Cancer, Deepak S. Chauhan, Meena Jaggi, Subhash C. Chauhan, Murali M. Yallapu

Research Symposium

Background: Rio Grande Valley experience severe cancer health disparity. A novel therapeutic modality may serve as better therapeutic option. Nanohybrids endowed with multifunctionality, longer circulation time, large surface area have emerged as an active preference for cancer research. However, rising concern of nanomaterials toxicity and scalability issues has slowed their translation to clinics. Exosomes (Exo) are endogenous endocytic origin 40-100 nm vesicles found in various body fluids, which in comparison to synthetic nanoparticles, are biodegradable, highly biocompatible as well as immunocompatible in nature. Although bulk isolation of exosomes from human body fluids is still a problem and engineering of exosomes …

Cyclophosphamide And Epirubicin Induce Apoptotic Cell Death In Microglia Cells, Rafael De La Hoz-Camacho

Research Symposium

Background. Chemotherapy Related Cognitive Impairment’s (CRCI), diminish patient’s quality life, being breast cancer (BC) patients the most affected. Microglia is described to play a major role in CRCI; hence, the aim of this research was to describe the cytotoxicity of cyclophosphamide (CTX) and Epirubicin (EPI), on microglia (SIM-A9), compared to BC cells (4T1).

Methods. We assessed cell viability (Resazurin) and cell death (AnnV), as well as nuclear damage with γ-H2AX, p53, p16 and cell cycle analysis (PI staining) by flow cytometry (FC). Furthermore, we evaluated ΔΨm (DIOC6), ROS (DCFDA) and NO (DAF-FM) production. Finally, caspase activation (TF2-VAD-FMK) and autophagy (CYTO-ID). …

Identification Of Tectorigenin As A Natural Pro-Hypoxia Compound: Implications In Modulation Of Cellular Differentiation And Senescence, Mallika Khurana, Renu Wadhwa, Sunil Kaul

Research Symposium

Background: Hypoxia, a suboptimal level of oxygen, evokes stress response in cells and activated hypoxia signaling has been largely established as a pro-metastasis and pro-angiogenic factor for tumor cells. On the other hand, age-related neurodegenerative disorders are characterized by hypoxic environment, accumulation of molecular garbage and induction of premature senescence. Several recent studies have reported anti-stress impact of the intermittent induction of hypoxia signaling in these cells.

Methods: Screening of a phytochemical library using Hypoxia Responsive Element (HRE) driven luciferase as a reporter was carried out to identify hypoxia-modulating phytochemicals. Activation of HIF-1a (master regulator of hypoxia signaling) was validated …

Identification Of The Functional Domain Of The Dense Core Vesicle Biogenesis Factor Hid-1, Blake H. Hummer, Theodore Carter, Breanna L. Sellers, Jenna D. Triplett, Cedric S. Asensio

Biological Sciences: Faculty Scholarship

Large dense core vesicles (LDCVs) mediate the regulated release of neuropeptides and peptide hormones. HID-1 is a trans-Golgi network (TGN) localized peripheral membrane protein contributing to LDCV formation. There is no information about HID-1 structure or domain architecture, and thus it remains unknown how HID-1 binds to the TGN and performs its function. We report that the N-terminus of HID-1 mediates membrane binding through a myristoyl group with a polybasic amino acid patch but lacks specificity for the TGN. In addition, we show that the C-terminus serves as the functional domain. Indeed, this isolated domain, when tethered to the TGN, …

Tmem27 Suppresses Tumor Development By Promoting Ret Ubiquitination, Positioning, And Degradation, Qianjin Guo, Zi-Ming Cheng, Hector Gonzalez-Cantú, Matthew Rotondi, Gabriela Huelgas-Morales, Purushoth Ethiraj, Zhijun Qiu, Jonathan Lefkowitz, Wan Song, Bethany N Landry, Hector Lopez, Cynthia M Estrada-Zuniga, Shivi Goyal, Mohammad Aasif Khan, Timothy J Walker, Exing Wang, Faqian Li, Yanli Ding, Lois M Mulligan, Ricardo C T Aguiar, Patricia L M Dahia

Faculty, Staff and Student Publications

The TMEM127 gene encodes a transmembrane protein of poorly known function that is mutated in pheochromocytomas, neural crest-derived tumors of adrenomedullary cells. Here, we report that, at single-nucleus resolution, TMEM127-mutant tumors share precursor cells and transcription regulatory elements with pheochromocytomas carrying mutations of the tyrosine kinase receptor RET. Additionally, TMEM127-mutant pheochromocytomas, human cells, and mouse knockout models of TMEM127 accumulate RET and increase its signaling. TMEM127 contributes to RET cellular positioning, trafficking, and lysosome-mediated degradation. Mechanistically, TMEM127 binds to RET and recruits the NEDD4 E3 ubiquitin ligase for RET ubiquitination and degradation via TMEM127 C-terminal PxxY motifs. Lastly, increased cell …

Effects Of Osmotic Stress On Oxygen Consumption Of Drosophila Cells (Kc167), Ali A. Ahmed, Rajib Hassan, Michael A. Menze

The Cardinal Edge

This article investigates the effect of osmotic stress on a drosophila cell line called Kc167.

The embryonic-derived fly (Drosophila melanogaster) cell line, Kc-167, was employed as a model for water-stress sensitivity in Arthropods. Like mammalian cells, cells derived from the fruit fly contain the same basic set of membranous components found in all eukaryotic cells. A series of experiments were conducted to characterize the mitochondrial repones of Kc167 cells to water stress. Precisely, the oxygen flux in a sealed respirometer chamber containing Kc167 cells was measured under hyperosmotic and control conditions. Mitochondrial uncouplers were used in some experiments for intact …

Examining Pi3k-Signaling-Dependent Regulation Of Lens Organelle Free Zone Formation Via Immunolocalization And Immunoblotting In Chick Embryos, Rifah Gheyas, A. Sue Menko

Computational Medicine Center Faculty Papers

The elimination of lens organelles during development, required for mature lens function, is an autophagy-dependent mechanism induced through suppression of PI3K signaling. Here, we present a protocol for investigating the signaling pathways responsible for induction of the formation of this lens organelle free zone. We describe steps for preparation of lens organ culture and use of signaling pathway inhibitors. We then detail procedures for analyzing their impact using both confocal microscopy imaging of immunolabeled lens cryosections and immunoblot approaches. For complete details on the use and execution of this protocol, please refer to Gheyas et al. (2022).

Canine Testes Thin Sections Culture​, Nguyen Khoi Nguyen, Ramanpreet Singh

2023 Symposium

Canine testes thin section culture

Testes tissue culture systems would provide a tool to elucidate spermatogenesis mechanisms, with the aim of genetic preservation of mammals, especially endangered species. Our experiment aims to develop a culture system capable of producing viable mammalian sperm cells in vitro.

Dogs were chosen as the model organism because testes are readily available. Canine testes were obtained from a local veterinary clinic. Thin sections were generated using a commercial electric slicer. They then were cleaned using Dulbecco’s Phosphate-Buffered Saline (DPBS) supplemented with antibiotics then cultured in a modified Tissue Culture Medium 199 (TCM-199). Sections were …

Canine Testes Thin Sections Culture, Nguyen Khoi Nguyen, Ramanpreet Singh

2023 Symposium

Canine testes thin section culture

Testes tissue culture systems would provide a tool to elucidate spermatogenesis mechanisms, with the aim of genetic preservation of mammals, especially endangered species. Our experiment aims to develop a culture system capable of producing viable mammalian sperm cells in vitro.

Dogs were chosen as the model organism because testes are readily available. Canine testes were obtained from a local veterinary clinic. Thin sections were generated using a commercial electric slicer. They then were cleaned using Dulbecco’s Phosphate-Buffered Saline (DPBS) supplemented with antibiotics then cultured in a modified Tissue Culture Medium 199 (TCM-199). Sections were …

Oligodendrocyte 2phatal Reveals Dynamics Of Myelin Degeneration And Repair, Timothy W. Chapman

Dartmouth College Ph.D Dissertations

Oligodendrocytes are responsible for producing myelin in the central nervous system. This lipid-rich coating along axons helps to increase action potential velocity, provide metabolic support to axons, and facilitate fine-tuning of neuronal circuitry. Demyelination and/or myelin dysfunction is widespread in neurodegenerative diseases and aging. Despite this, we know very little about how individual oligodendrocytes, or the myelin sheaths they produce, degenerate. Myelin repair, carried out by resident oligodendrocyte precursor cells (OPCs), is known to occur following myelin damage in certain contexts. We sought to investigate the cellular dynamics of oligodendrocyte degeneration and repair by developing a non-inflammatory demyelination model, combining …

Transcriptional Pausing Factor M1bp Regulates Cellular Homeostasis By Suppressing Autophagy And Apoptosis In Drosophila Eye, Anuradha Venkatakrishnan Chimata, Hannah Darnell, Akanksha Raj, Madhuri Kango-Singh

Biology Faculty Publications

During organogenesis cellular homeostasis plays a crucial role in patterning and growth. The role of promoter proximal pausing of RNA polymerase II, which regulates transcription of several developmental genes by GAGA factor or Motif 1 Binding Protein (M1BP), has not been fully understood in cellular homeostasis. Earlier, we reported that M1BP, a functional homolog of ZKSCAN3, regulates wingless (wg) and caspase-dependent cell death (apoptosis) in the Drosophila eye. Further, blocking apoptosis does not fully rescue the M1BP^RNAi phenotype of reduced eye. Therefore, we looked for other possible mechanism(s). In a forward genetic screen, members of the Jun-amino-terminal-(NH2)-Kinase (JNK) pathway …

Molecular Mechanisms Regulating Prometaphase And Metaphase States For Faithful Chromosome Segregation, Sarah Yvette Valles

Dartmouth College Ph.D Dissertations

Cells progress through different stages of the cell cycle as they ultimately prepare to divide during mitosis. Mitosis relies on many interconnected networks to carry out the coordinated events required for faithful chromosome segregation. When a cell enters mitosis, chromosomes are highly condensed and sister chromatids are held together by cohesion. Kinetochores assemble at the constricted regions on each chromosome. The kinetochore is a large macromolecular structure composed of many proteins that form the binding site for microtubules of the mitotic spindle to attach. These kinetochore-microtubule (k-MT) attachments serve to align chromosomes at the center of the cell and are …