Open Access. Powered by Scholars. Published by Universities.®

Cell Biology Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 30 of 34

Full-Text Articles in Cell Biology

The Role Of Rnf4 In Stripping Transcriptionally-Active Huntingtin, Jen Peek Dec 2017

The Role Of Rnf4 In Stripping Transcriptionally-Active Huntingtin, Jen Peek

Undergraduate Honors Theses

Altered gene expression is a hallmark of neurodegenerative disorders such as Huntington’s disease. The causative agent of Huntington’s is a mutant, aggregation-prone fragment of huntingtin (htt) that aggregates in the cytosol and nuclei of neuronal cells. The severity and onset of Huntington’s is correlated with the length of a polyglutamine (Q) tract encoded in the N-terminus of htt. Little is known about the nuclear accumulation of polyQ expanded htt, how it interacts with chromatin, and dysregulates transcriptional activity. In this thesis, we investigate the effect of nuclear localized htt on reporter gene activation and demonstrate that the ...


A Study Of A Novel Self-Fertility Mechanism In The Hermaphroditic Nematode Rhabditis Sp. Sb347, Xiaoxue Lin May 2017

A Study Of A Novel Self-Fertility Mechanism In The Hermaphroditic Nematode Rhabditis Sp. Sb347, Xiaoxue Lin

Undergraduate Honors Theses

Germ cell development and gametogenesis are essential for the continuity of future generations in most eukaryotic organisms, including humans. One well-established system for studying the complex mechanisms of gametogenesis is the nematode species, Caenorhabditis elegans. The fact that C. elegans hermaphrodite germlines undergo different cellular development at the same life stage in a linear progression makes C. elegans a model system for the study of the conversion of uncommitted germ cells into either oocytes or sperm. C. elegans hermaphrodite produces spermatocytes during the final larval stage and then makes a one-time switch over to oogenesis as the worm enters adulthood ...


Variations In Flanking Residues Of Thyroid Hormone Receptor Alpha1 Isoform, Christine W. Gao May 2017

Variations In Flanking Residues Of Thyroid Hormone Receptor Alpha1 Isoform, Christine W. Gao

Undergraduate Honors Theses

The thyroid hormone receptor (TR) is a transcription factor that represses or activates genes whose regulatory regions bear thyroid hormone (T3) response elements (TREs). Modulation of this function requires shuttling into and out of the nucleus. This is mediated by the binding of importins and exportins to amino acid sequences within TR, called nuclear localization signals (NLSs) and nuclear export signals (NESs), respectively. The fine balance between nuclear import, retention, and export of TR has emerged as a critical control point for modulating T3-responsive gene expression, including genes that control cell proliferation, differentiation, and apoptosis. NLS-2 is a specific NLS ...


Receptor Gone Rogue: Investigating Localization Of A Cancerous Thyroid Hormone Receptor, Michelle Barbeau May 2017

Receptor Gone Rogue: Investigating Localization Of A Cancerous Thyroid Hormone Receptor, Michelle Barbeau

Undergraduate Honors Theses

Thyroid hormone receptors play a crucial role in regulating differentiation, growth and development in response to thyroid hormone, and mutations in these receptors can have severe medical consequences ranging from endocrine dysfunction to cancer. Tumors of patients with hepatocellular carcinoma (HCC) display a high incidence of mutant thyroid hormone receptors (TRs), and one such mutant is TRα1 (K74E, A264V). The binding partners and gene targets of this mutant have been characterized, but the role of intracellular localization in the pathogenesis of TRα1 (K74E, A264V) has not yet been determined. Here, it was observed that the mutant receptor has a tendency ...


Beyond "Self-Eating": The Role Of The Pseudophosphatase Mk-Styx In Regulating Autophagy, Patrick Christian May 2017

Beyond "Self-Eating": The Role Of The Pseudophosphatase Mk-Styx In Regulating Autophagy, Patrick Christian

Undergraduate Honors Theses

Cells carry out their day to day functions through the cellular work horses, proteins. Proteins work together like bees in a hive, each having its own specific task to accomplish. This specificity creates a fine-tuned division of labor where different types of proteins work together, completing their own work for the overall functioning of the cell. This division of labor can be mapped out nicely with cellular pathways. One such pathway is the stress response pathway. One of the major “workers” in this pathway is MK-STYX [MAPK (mitogen-activated protein kinase) phosphoserine/threonine/tyrosine-binding protein]. MK-STYX is a pseudophosphatase, a member ...


Cytological And Bioinformatical Analysis Of Spe-26, A C. Elegans Kelch-Like Protein That Functions During The Karyosome Stage Of Spermatogenesis, Stephen A. Gurley Apr 2017

Cytological And Bioinformatical Analysis Of Spe-26, A C. Elegans Kelch-Like Protein That Functions During The Karyosome Stage Of Spermatogenesis, Stephen A. Gurley

Undergraduate Honors Theses

Prior to the meiotic divisions, spermatocytes undergo extended developmental processing termed meiotic prophase. As these spermatocytes transition out of meiotic prophase, they must cease transcription and prepare the chromosomes for the meiotic division. Our knowledge of the mechanisms that drive this transition remains incomplete.

In this study, we analyze through cytological and bioinformatics methods a poorly understood Kelch-like protein required for Caenorhabditis elegans spermatogenesis, SPE-26. Analysis of spe-26 mutants reveals precocious meiotic spindle maturation relative to chromatin morphology beginning during the poorly-understood spermatogenesis-specific karyosome stage of late meiotic prophase. spe-26 spermatocytes also display chromosome alignment and segregation defects during the ...


Sumo-Targeted Ubiquitin Ligase (Stubl) Slx5 Regulates Proteolysis Of Centromeric Histone H3 Variant Cse4 And Prevents Its Mislocalization To Euchromatin, Kentaro Ohkuni, Yoshimitsu Takahashi, Alyona Flup, Josh La, Wei-Chun Au, Nagesh Pasupala, Ruben Levy-Meyers, Jack Warren, Alexander Strunnikov, Richard E. Baker, Oliver Kerscher, Kerry Bloom, Munira A. Basrai May 2016

Sumo-Targeted Ubiquitin Ligase (Stubl) Slx5 Regulates Proteolysis Of Centromeric Histone H3 Variant Cse4 And Prevents Its Mislocalization To Euchromatin, Kentaro Ohkuni, Yoshimitsu Takahashi, Alyona Flup, Josh La, Wei-Chun Au, Nagesh Pasupala, Ruben Levy-Meyers, Jack Warren, Alexander Strunnikov, Richard E. Baker, Oliver Kerscher, Kerry Bloom, Munira A. Basrai

Arts & Sciences Articles

Centromeric histone H3, CENP-ACse4, is essential for faithful chromosome segregation. Stringent regulation of cellular levels of CENP-ACse4 restricts its localization to centromeres. Mislocalization of CENP-ACse4 is associated with aneuploidy in yeast and flies and tumorigenesis in human cells; thus defining pathways that regulate CENP-A levels is critical for understanding how mislocalization of CENP-A contributes to aneuploidy in human cancers. Previous work in budding yeast shows that ubiquitination of overexpressed Cse4 by Psh1, an E3 ligase, partially contributes to proteolysis of Cse4. Here we provide the first evidence that Cse4 is sumoylated by E3 ligases Siz1 and Siz2 in vivo and ...


Characterizing Importin Binding To Thyroid Hormone Receptor Α1, Emma Lynn Mcgregor Apr 2016

Characterizing Importin Binding To Thyroid Hormone Receptor Α1, Emma Lynn Mcgregor

Undergraduate Honors Theses

Thyroid hormone, or T3, is essential in many bodily functions, from early development to the maintenance of health in adults. It is crucial for growth and skeletal development, development of the nervous system, cell differentiation, and maintenance of metabolic balance. The thyroid hormone receptor, TR, is a major mediator of thyroid hormone action. TR is a transcription factor and able to activate or repress transcription depending on the binding of its ligand, T3. There are two isoforms of TR, encoded by different genes: TRα and TRβ. Each of these isoforms have multiple alternative splicing products.

While TR’s ...


Genetic And Cytological Analysis Of Spe-6, A C. Elegans Tau Tubulin Kinase, Jackson J. Peterson May 2015

Genetic And Cytological Analysis Of Spe-6, A C. Elegans Tau Tubulin Kinase, Jackson J. Peterson

Undergraduate Honors Theses

To acquire motility, Caenorhabditis elegans sperm must undergo the

regulated cellular remodeling process of sperm activation, but in the complete

absence of new protein synthesis. Nematode sperm utilize two general

mechanisms to overcome this obstacle: 1) They pre-package many proteins

involved in this remodeling and subsequent sperm motility within the unique

Fibrous Body-Membranous Organelle (FB-MOs) complexes; 2) They employ

large numbers of protein kinases and phosphatases, including SPE-6, in the

acquisition and regulation of motility. Genetically, spe-6 is represented by two

classes of alleles. In null alleles, spermatocytes fail to assemble FB-MOs or

complete their meiotic divisions. In a second ...


Apoptosis And Cell Cycle Regulation As Mechanisms Of Compensation From Notch Signaling Perturbation In The Developing Nervous System Of Xenopus Laevis, Catherine Hope Bianchi Jan 2015

Apoptosis And Cell Cycle Regulation As Mechanisms Of Compensation From Notch Signaling Perturbation In The Developing Nervous System Of Xenopus Laevis, Catherine Hope Bianchi

Dissertations, Theses, and Masters Projects

No abstract provided.


Evolutionary Conservation Of A Modified Spermatogenesis Program In Rhabditis Nematodes With Skewed Sex Ratios, Ethan S. Winter May 2014

Evolutionary Conservation Of A Modified Spermatogenesis Program In Rhabditis Nematodes With Skewed Sex Ratios, Ethan S. Winter

Undergraduate Honors Theses

The cellular divisions in Rhabditis sp. SB347 male spermatogenesis have been modified to re-purpose an asymmetric division. This results in the dramatically skewed sex ratios observed in the progeny of males of this species. Here we confirm this asymmetry in the division of tubulin and major sperm protein (MSP). MSP, a necessary sperm component, is segregated exclusively into spermatids bearing the X chromosome while tubulin is segregated into the nullo-X sperm. Timing of the partitioning events reveals that MSP migration is not directly dependent on tubulin spindle asymmetry. Additionally, the endoplasmic reticulum is also segregated asymmetrically to the nullo-X spermatid ...


Modeling Drosophila Stem Cell Development Through Ex Vivo Live-Cell Imaging Studies, Mohima Sanyal Apr 2014

Modeling Drosophila Stem Cell Development Through Ex Vivo Live-Cell Imaging Studies, Mohima Sanyal

Undergraduate Honors Theses

Stem cell specification, maintenance, and differentiation are imperative to proper organogenesis and tissue maintenance. Understanding the mechanisms and steps of these developmental processes is invaluable to advancing tissue grafting, cancer treatment, and other organ therapies. The Drosophila melanogaster testis is one of the best-characterized systems for studying these processes. Currently, studies in the Drosophila testis have thoroughly characterized when stem cells develop and what the resulting adult testis morphology will be. A major question that remains to be answered is how stem cells develop – what controls what cells become functional stem cells and how stem cell fates are dictated. To ...


The Sumo-Targeted Ubiquitin Ligase Rnf4 Regulates The Localization And Function Of The Htlv-1 Oncoprotein Tax, Kimberly A. Fryrear, Xin Guo, Oliver Kerscher, O John Semmes Jan 2012

The Sumo-Targeted Ubiquitin Ligase Rnf4 Regulates The Localization And Function Of The Htlv-1 Oncoprotein Tax, Kimberly A. Fryrear, Xin Guo, Oliver Kerscher, O John Semmes

Arts & Sciences Articles

The Really Interesting New Gene (RING) Finger Protein 4 (RNF4) represents a class of ubiquitin ligases that target Small Ubiquitin-like Modifier (SUMO)–modified proteins for ubiquitin modification. To date, the regulatory function of RNF4 appears to be ubiquitin-mediated degradation of sumoylated cellular proteins. In the present study, we show that the Human T-cell Leukemia Virus Type 1 (HTLV-1) oncoprotein Tax is a substrate for RNF4 both in vivo and in vitro. We mapped the RNF4-binding site to a region adjacent to the Tax ubiquitin/SUMO modification sites K280/K284. Interestingly, RNF4 modification of Tax protein results in relocalization of the ...


Flow Cytometric Analyses On The Activation, Proliferation, And Differentiation State Of B Cells In Rainbow Trout (Oncorhynchus Mykiss), Maggie Jeanne Barr Jan 2010

Flow Cytometric Analyses On The Activation, Proliferation, And Differentiation State Of B Cells In Rainbow Trout (Oncorhynchus Mykiss), Maggie Jeanne Barr

Dissertations, Theses, and Masters Projects

No abstract provided.


The Pax-5 Gene Is Alternatively Spliced In Trout B Cells, Raaj Mahendra Talauliker Jan 2010

The Pax-5 Gene Is Alternatively Spliced In Trout B Cells, Raaj Mahendra Talauliker

Dissertations, Theses, and Masters Projects

No abstract provided.


Sperm-Oocyte Membrane Interactions During Fertilization In The Nematode Caenorhabditis Elegans, Alissa Gale Richmond Jan 2004

Sperm-Oocyte Membrane Interactions During Fertilization In The Nematode Caenorhabditis Elegans, Alissa Gale Richmond

Dissertations, Theses, and Masters Projects

No abstract provided.


Recognizing Chromosomes In Trouble: Association Of The Spindle Checkpoint Protein Bub3p With Altered Kinetochores And A Unique Defective Centromere, Oliver Kerscher, Luciana B. Crotti, Munira A. Basrai Sep 2003

Recognizing Chromosomes In Trouble: Association Of The Spindle Checkpoint Protein Bub3p With Altered Kinetochores And A Unique Defective Centromere, Oliver Kerscher, Luciana B. Crotti, Munira A. Basrai

Arts & Sciences Articles

Spindle checkpoint proteins monitor the interaction of the spindle apparatus with the kinetochores, halting anaphase even if the microtubule attachment of only a single chromosome is altered. In this study, we show that Bub3p of Saccharomyces cerevisiae, an evolutionarily conserved spindle checkpoint protein, exhibits distinct interactions with an altered or defective kinetochore(s). We show for the first time that green fluorescent protein-tagged S. cerevisiae Bub3p (Bub3-GFP) exhibits not only a diffuse nuclear localization pattern but also forms distinct nuclear foci in unperturbed growing and G2/M-arrested cells. As Bub3-GFP foci overlap only a subset of kinetochores, we tested ...


Cloning And Functional Characterization Of Hypoxia-Inducible Factor 1alpha Upstream Regions In Xenopus Laevis, Conor W. Sipe Jan 2003

Cloning And Functional Characterization Of Hypoxia-Inducible Factor 1alpha Upstream Regions In Xenopus Laevis, Conor W. Sipe

Dissertations, Theses, and Masters Projects

No abstract provided.


The Yeast Nuclear Pore Complex Functionally Interacts With Components Of The Spindle Assembly Checkpoint, Tatiana Louk, Oliver Kerscher, Robert J. Scott, Munira A. Basrai, Richard W. Wozniak Dec 2002

The Yeast Nuclear Pore Complex Functionally Interacts With Components Of The Spindle Assembly Checkpoint, Tatiana Louk, Oliver Kerscher, Robert J. Scott, Munira A. Basrai, Richard W. Wozniak

Arts & Sciences Articles

Aphysical and functional link between the nuclear pore complex (NPC) and the spindle checkpoint machinery has been established in the yeast Saccharomyces cerevisiae. We show that two proteins required for the execution of the spindle checkpoint, Mad1p and Mad2p, reside predominantly at the NPC throughout the cell cycle. There they are associated with a subcomplex of nucleoporins containing Nup53p, Nup170p, and Nup157p. The association of the Mad1p–Mad2p complex with the NPC requires Mad1p and is mediated in part by Nup53p. On activation of the spindle checkpoint, we detect changes in the interactions between these proteins, including the release of ...


Tim18p Is A New Component Of The Tim54p-Tim22p Translocon In The Mitochondrial Inner Membrane, Oliver Kerscher, Naresh B. Sepuri, Robert E. Jensen Jan 2000

Tim18p Is A New Component Of The Tim54p-Tim22p Translocon In The Mitochondrial Inner Membrane, Oliver Kerscher, Naresh B. Sepuri, Robert E. Jensen

Arts & Sciences Articles

The mitochondrial inner membrane contains two separate translocons: one required for the translocation of matrix-targeted proteins (the Tim23p-Tim17p complex) and one for the insertion of polytopic proteins into the mitochondrial inner membrane (the Tim54p-Tim22p complex). To identify new members of the Tim54p-Tim22p complex, we screened for high-copy suppressors of the temperature-sensitivetim54-1 mutant. We identified a new gene,TIM18, that encodes an integral protein of the inner membrane. The following genetic and biochemical observations suggest that the Tim18 protein is part of the Tim54p-Tim22p complex in the inner membrane: multiple copies of TIM18 suppress thetim54-1 growth defect; thetim18 ...


Cell-Cell Interactions In The Development Of The Vascular System Of Xenopus, Krista Marie Stimson Jan 1998

Cell-Cell Interactions In The Development Of The Vascular System Of Xenopus, Krista Marie Stimson

Dissertations, Theses, and Masters Projects

No abstract provided.


The Tim54p–Tim22p Complex Mediates Insertion Of Proteins Into The Mitochondrial Inner Membrane, Oliver Kerscher, Jason Holder, Maithreyan Srinivasan, Roxanne S. Leung, Robert E. Jensen Dec 1997

The Tim54p–Tim22p Complex Mediates Insertion Of Proteins Into The Mitochondrial Inner Membrane, Oliver Kerscher, Jason Holder, Maithreyan Srinivasan, Roxanne S. Leung, Robert E. Jensen

Arts & Sciences Articles

We have identified a new protein, Tim54p, located in the yeast mitochondrial inner membrane. Tim54p is an essential import component, required for the insertion of at least two polytopic proteins into the inner membrane, but not for the translocation of precursors into the matrix. Several observations suggest that Tim54p and Tim22p are part of a protein complex in the inner membrane distinct from the previously characterized Tim23p-Tim17p complex. First, multiple copies of the TIM22 gene, but not TIM23 or TIM17, suppress the growth defect of a tim54-1 temperature-sensitive mutant. Second, Tim22p can be coprecipitated with Tim54p from detergent-solubilized mitochondria, but ...


The Effects Of Contaminated Sediment On The Epidermal Goblet Cells Of The Mummichog, Fundulus Heteroclitus, Laurent C. Mézin Jan 1994

The Effects Of Contaminated Sediment On The Epidermal Goblet Cells Of The Mummichog, Fundulus Heteroclitus, Laurent C. Mézin

Dissertations, Theses, and Masters Projects

Secretion of mucus by epidermal goblet cells is an important first line of defense for teleosts. It protects them against many of the biological, physical and chemical insults they encounter in their environment. This project monitored changes in hemoglobin concentration in epidermal mucus and in the density, diameter and mucus quality of epidermal goblet cells in the mummichog, Fundulus heteroclitus, following exposure to creosote-contaminated sediment. Male fish (200) were exposed for 13 days in flowthough aquaria to either an uncontaminated reference sediment or contaminated sediment containing 30% Elizabeth River sediment. Fish were sampled on Days 0, 3, 7 and 13 ...


Cell Division In The Multicellular Marine Red Alga Agardhiella Subulata, Karel Joan Klepacki Jan 1994

Cell Division In The Multicellular Marine Red Alga Agardhiella Subulata, Karel Joan Klepacki

Dissertations, Theses, and Masters Projects

No abstract provided.


Ultrastructure And Mitosis Of Glaucosphaera Vacuolata, Steven Philip Allan Goss Jan 1993

Ultrastructure And Mitosis Of Glaucosphaera Vacuolata, Steven Philip Allan Goss

Dissertations, Theses, and Masters Projects

No abstract provided.


Ultrastructural Analysis Of Vegetative And Mitotic Cells Of The Unicellular Red Alga Rhodella Violacea, Laura May Patrone Jan 1988

Ultrastructural Analysis Of Vegetative And Mitotic Cells Of The Unicellular Red Alga Rhodella Violacea, Laura May Patrone

Dissertations, Theses, and Masters Projects

No abstract provided.


The Ultrastructure Of Cell Division In The Marine Red Alga Lomentaria Baileyana, Elizabeth Carpenter Davis Jan 1984

The Ultrastructure Of Cell Division In The Marine Red Alga Lomentaria Baileyana, Elizabeth Carpenter Davis

Dissertations, Theses, and Masters Projects

No abstract provided.


Ultra Structure Of Cell Division In The Unicellular Red Alga Porphyridium Purpureum, Kathleen L. Schornstein Jan 1981

Ultra Structure Of Cell Division In The Unicellular Red Alga Porphyridium Purpureum, Kathleen L. Schornstein

Dissertations, Theses, and Masters Projects

No abstract provided.


Temperature-Dependency Of Transformation And Cell Cycle Length In Human Lymphocytes, John Patrick Mcgee Jan 1981

Temperature-Dependency Of Transformation And Cell Cycle Length In Human Lymphocytes, John Patrick Mcgee

Dissertations, Theses, and Masters Projects

No abstract provided.


The Osmotic Fragility Of Red Blood Cells Of Marine Animals: A Comparative Study, Robert Demanche Jan 1980

The Osmotic Fragility Of Red Blood Cells Of Marine Animals: A Comparative Study, Robert Demanche

Dissertations, Theses, and Masters Projects

No abstract provided.