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Developmental Biology

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Full-Text Articles in Molecular Biology

Mechanisms Of Oriented Cell Division And Their Roles In Tissue Development, Evan Blake Dewey Apr 2019

Mechanisms Of Oriented Cell Division And Their Roles In Tissue Development, Evan Blake Dewey

Biology ETDs

Properly executed cell division is crucial to development, maintenance, and longevity of multicellular organisms. Defects in both symmetric and asymmetric divisions can lead to improper developmental patterning, as well as genomic instability, disruption of tissue homeostasis, and cancer. Our research focuses on how regulators orchestrate proper cell divisions. Mushroom Body Defect (Mud) is one such regulator, and here we describe how Mud is regulated via the Hippo signaling pathway kinase Warts (Wts), showing Wts phosphorylates Mud to enhance interaction with the polarity protein Partner of Inscuteable, promoting spindle orientation activity. We next focus on another regulator, Shortstop (Shot), describing a ...


Molecular Homology & The Ancient Genetic Toolkit: How Evolutionary Development Could Shape Your Next Doctor's Appointment, Elizabeth G. Plender Jan 2019

Molecular Homology & The Ancient Genetic Toolkit: How Evolutionary Development Could Shape Your Next Doctor's Appointment, Elizabeth G. Plender

All Regis University Theses

Homology, i.e. the biological pattern of “sameness,” is a pervasive facet of evolution at both the organismic and molecular levels of organization. While traditionally interpreted at the anatomical scale, shared molecular phenotypes across vastly divergent species hint at the presence of a deeply conserved, ancient genetic “toolkit” characteristic of the animal kingdom. Through careful examination of the nuanced homologues implicated in comparative embryology, evolutionary developmental biologists provide a holistic approach to understanding how homologous patterns of gene regulation translate to anatomical similarities among animal species. My summer research project in the Division of Developmental Biology at Cincinnati Children’s ...


Development And Characterization Of An Immunologically Humanized And Cancer Xenograft Model In Pigs With Severe Combined Immunodeficiency (Scid), Adeline Nicole Boettcher Jan 2019

Development And Characterization Of An Immunologically Humanized And Cancer Xenograft Model In Pigs With Severe Combined Immunodeficiency (Scid), Adeline Nicole Boettcher

Graduate Theses and Dissertations

Swine with severe combined immunodeficiency (SCID) are an emerging large animal model for biomedical research. There have been several SCID pig models described since our first discovery of naturally occurring SCID with mutations in Artemis (DCLRE1C) in 2012. SCID animals are particularly useful in biomedical research due to their lack of T, B, and sometimes NK cells. Absence of the adaptive immune system allows for human cell and tissue xenotransplantation into these SCID animals. The works described within this thesis are categorized under four main goals: (1) further characterization of the immune system of Art-/- SCID pigs, (2) development of ...


Evaluation Of Motor Cortex Neuronal Morphology In Developmental Hyperserotonemia Rat Model, Colten Z. Dillinger Dec 2018

Evaluation Of Motor Cortex Neuronal Morphology In Developmental Hyperserotonemia Rat Model, Colten Z. Dillinger

MSU Graduate Theses

Fetal serotonin levels are involved in the development of the serotonergic system in an autoregulatory manner as well as the organization and connectivity of non-serotonergic neurons. Insufficient serotonin levels during development result in improper neuronal maturation and decreased synaptogenesis. Conversely, excess developmental serotonin levels can alter the progression of serotonergic neurons, ultimately resulting in a chronic decrease of serotonin in the developed brain via a negative feedback mechanism. There is a known correlation between autistic patients and chronically decreased brain serotonin concentrations; this is potentially implicated in the impaired development of the autistic brain. Incomplete or delayed development of motor ...


Effect Of Arsenic Exposure On Early Eye Development In Zebrafish (Danio Rerio), Remy S. Babich Aug 2018

Effect Of Arsenic Exposure On Early Eye Development In Zebrafish (Danio Rerio), Remy S. Babich

Electronic Theses and Dissertations

Arsenic is a metalloid that contaminates drinking water supplies worldwide. Due to concerns for human health, the World Health Organization (WHO) and the U.S. Environmental Protection Agency (EPA) have established a safe level in drinking water of ≤ 10 ppb. Arsenic has been shown to have carcinogenic effects in humans at high and low doses. Chronic exposure may result in dermal conditions such as hyperkeratosis and hyperpigmentation. Recently, arsenic exposure has also been linked to lower IQ values in children. The effect of arsenic on neurogenesis, specifically eye development, has not been widely explored. This study aimed to examine the ...


Mechanisms Of Age-Related Prostate Growth And Tumorigenesis, Deon O'Bryant May 2018

Mechanisms Of Age-Related Prostate Growth And Tumorigenesis, Deon O'Bryant

Electronic Theses & Dissertations Collection for Atlanta University & Clark Atlanta University

Prostate cancer is the most commonly diagnosed malignancy among men, but few genetic factors that drive prostate cancer initiation have been identified. The WD repeat domain 77 (Wdr77) protein is essential for cellular proliferation when it localizes in the cytoplasm of epithelial cells at the early stage of prostate development. In the adult prostate, it is transported into the nucleus and functions as a co-regulator of the androgen receptor to promote cellular differentiation and prostate function. This developmental process is reversed during prostate tumorigenesis i.e., Wdr77 is translocated from the nucleus into the cytoplasm to drive proliferation of prostate ...


Exploring The Role Of Tet1 In Genomic Imprinting, Jennifer Myers Sanmiguel Jan 2018

Exploring The Role Of Tet1 In Genomic Imprinting, Jennifer Myers Sanmiguel

Publicly Accessible Penn Dissertations

DNA methylation is an essential epigenetic mark crucial for normal mammalian development. This modification controls the expression of a unique class of genes, designated as imprinted, which are expressed monoallelically and in a parent-of-origin-specific manner. Proper parental allele-specific DNA methylation at imprinting control regions (ICRs) is necessary for appropriate imprinting. Processes that deregulate DNA methylation of imprinted loci cause disease in humans. DNA methylation patterns dramatically change during mammalian development: first, the majority of the genome, with the exception of ICRs, is demethylated after fertilization, and subsequently undergoes genome-wide de novo DNA methylation. Secondly, after primordial germ cells are specified ...


Discovering Novel Hearing Loss Genes: Roles For Esrp1 And Gas2 In Inner Ear Development And Auditory Function, Alex Martin Rohacek Jan 2018

Discovering Novel Hearing Loss Genes: Roles For Esrp1 And Gas2 In Inner Ear Development And Auditory Function, Alex Martin Rohacek

Publicly Accessible Penn Dissertations

Hearing loss is the most common form of congenital birth defect, affecting an estimated

35 million children worldwide. To date, nearly 100 genes have been identified which

contribute to a deafness phenotype in humans, however, many cases remain in which a

causative mutation has yet to be found. In addition, the exact mechanism by which

hearing loss occurs in the presence of many of these mutations is still not understood.

This is due, in part, to the complex nature of the development and function of the

cochlear duct, the organ of hearing. The cochlea undergoes an intricate morphogenetic

development and ...


Targets And Functions Of The Microrna-200 Family In The Developing Skin And Hair Follicle, Jaimee Elizabeth Hoefert Jan 2018

Targets And Functions Of The Microrna-200 Family In The Developing Skin And Hair Follicle, Jaimee Elizabeth Hoefert

Molecular, Cellular, and Developmental Biology Graduate Theses & Dissertations

The microRNA-200 (miR-200) family is well known for preventing epithelial-to-mesenchymal transition in cancer. However, the targets and functions of this family in normal epithelial tissues remain unclear. This five-member microRNA (miRNA) family also presents a unique platform for studying miRNA-mediated regulation, as they share two nearly-identical seed sequences. The results presented within this dissertation establish a role for these miRNAs in governing hair follicle morphogenesis and fine-tuning cell specification by regulating cell adhesion, polarity, and signaling pathways. By directly ligating miRNAs to their targeted mRNA regions, numerous miR-200 family targets are identified, many of which are involved ...


Characterization Of A Mucopolysaccharidosis Type I And Galnac Transferase Deficiency Double Knockout Mouse, Karan Gera Jan 2018

Characterization Of A Mucopolysaccharidosis Type I And Galnac Transferase Deficiency Double Knockout Mouse, Karan Gera

Graduate Theses and Dissertations

The mucopolysaccharidoses (MPSs) are a group of lysosomal storage diseases (LSDs) which are characterized by the aberrant primary storage of glycosaminoglycans (GAGs) in lysosomes of multiple organ and tissue systems. The most commonly diagnosed is MPS Type I (MPS I), caused by mutations in the gene which codes for α-L-iduronidase (IDUA). Biochemically, MPS I is characterized by the aberrant primary lysosomal storage of incompletely degraded dermatan and heparan sulfates, along with a secondary accumulation of gangliosides and other compounds in lysosomes. Its clinical manifestation in severe form leads to early death, characterized by progressive central nervous system disease (with behavioral ...


Wnt Secretion Proteins Modulate Rankl-Induced Expression Of Aire In Thymic Epithelial Cells, Daniel Pollack Jan 2018

Wnt Secretion Proteins Modulate Rankl-Induced Expression Of Aire In Thymic Epithelial Cells, Daniel Pollack

Dissertations and Theses

Thymic epithelial cells (TEC) are essential for a proper adaptive immune response by regulating thymocyte development and establishing central tolerance. In the thymus, TECs differentially express Wnt proteins, which activate canonical and non-canonical Wnt signaling pathways. Wnt signaling is thought to regulate cell survival, proliferation, and development although the direct molecular mechanisms in TECs have yet to be elucidated. The inducible inhibition of canonical Wnt signaling with Dkk1 leads to a rapid loss of TEC progenitors as well as a decline in mature Aire-expressing mTECs. Therefore, we explore the role of Wnt ligands potentially responsible for stimulating and/or regulating ...


Regulation Of The Fgf/Erk Signaling Pathway: Roles In Zebrafish Gametogenesis And Embryogenesis, Jennifer M. Maurer Oct 2017

Regulation Of The Fgf/Erk Signaling Pathway: Roles In Zebrafish Gametogenesis And Embryogenesis, Jennifer M. Maurer

GSBS Dissertations and Theses

Signaling cascades, such as the extracellular signal-regulated kinase (ERK) pathway, play vital roles in early vertebrate development. Signals through these pathways are initiated by a growth factor or hormone, are transduced through a kinase cascade, and result in the expression of specific downstream genes that promote cellular proliferation, growth, or differentiation. Tight regulation of these signals is provided by positive or negative modulators at varying levels in the pathway, and is required for proper development and function. Two members of the dual-specificity phosphatase (Dusp) family, dusp6 and dusp2, are believed to be negative regulators of the ERK pathway and are ...


Gcn5 Impacts Fgf Signaling At Multiple Levels And Activates C-Myc Target Genes During Early Differentiation Of Embryoid Bodies, Li Wang Aug 2017

Gcn5 Impacts Fgf Signaling At Multiple Levels And Activates C-Myc Target Genes During Early Differentiation Of Embryoid Bodies, Li Wang

UT GSBS Dissertations and Theses (Open Access)

Precise control of gene expression during development is orchestrated by transcription factors, signaling pathways and co-regulators, with complex cross-regulatory events often occurring. Growing evidence has identified chromatin modifiers as important regulators for development as well, yet how particular chromatin modifying enzymes affect specific developmental processes remains largely unclear. Embryonic stem cells (ESCs) are self-renewing, pluripotent, and have the abilities to generate almost all cell types in adult tissues. The dual capacity of ESCs to self-renew and differentiate offers unlimited potential for studying gene regulation events at specific developmental stages in vitro that parallel developmental events during embryogenesis in vivo.

In ...


The Dlk1-Meg3 Locus In Malignant Cells Of Proposed Primordial Germ Cell Origins., Zachariah Payne Sellers Aug 2017

The Dlk1-Meg3 Locus In Malignant Cells Of Proposed Primordial Germ Cell Origins., Zachariah Payne Sellers

Electronic Theses and Dissertations

Primordial germ cells (PGCs) are hypothesized to deposit hematopoietic stem cells (HSCs) along their migration route through the embryo during the early stages of embryogenesis. PGCs also undergo global chromatin remodeling, including the erasure and reestablishment of genomic imprints, during this migration. While PGCs do not spontaneously form teratomas, their malignant development into germ cell tumors (GCTs) in vivo is often accompanied by the retention of hypomethylation at the IGF2-H19 imprinting control differentially methylated region (DMR). Previous studies in bimaternal embryos determined that proper genomic imprinting at two paternally imprinted loci was necessary for their growth and development: Igf2-H19 and ...


Transcriptional And Post-Transcriptional Regulation Of Histone Variant H2a.Z During Sea Urchin Development, Mihai Hajdu Feb 2017

Transcriptional And Post-Transcriptional Regulation Of Histone Variant H2a.Z During Sea Urchin Development, Mihai Hajdu

All Dissertations, Theses, and Capstone Projects

Histone variant H2A.Z promotes chromatin accessibility at transcriptional regulatory elements and is developmentally regulated in metazoans. We characterize the transcriptional and post-transcriptional regulation of H2A.Z in the purple sea urchin Strongylocentrotus purpuratus. H2A.Z depletion by antisense translation-blocking morpholino oligonucleotides during early development causes developmental collapse, in agreement with its previously demonstrated general role in transcriptional multipotency. During H2A.Z peak expression in 24-h embryos, endogenous H2A.Z 3’ UTR sequences stabilize GFP mRNAs relative to those with SV40 3’ UTR sequences, although the 3’UTR of H2A.Z does not determine the spatial distribution of H2A.Z ...


Histone Variant Macroh2a In The Gut And Beyond: A Study Of Intestinal Fortitude, Ryan James Cedeno Jan 2017

Histone Variant Macroh2a In The Gut And Beyond: A Study Of Intestinal Fortitude, Ryan James Cedeno

Publicly Accessible Penn Dissertations

Epigenetic factors guide chromatin remodeling during cell state transitions and confer resistance to genotoxic stressors that could induce deleterious transformations. A particularly peculiar component of the epigenome with emerging roles in fine-tuning cell identity and upholding genomic stability is the structural histone variant macroH2A. Relatively little is currently known about macroH2A’s influence on overall cell developmental potency and less still is known about macroH2A’s contributions to adult stem cell identity and function in vivo. In this work, we use induced pluripotent stem cell (iPSC) reprogramming and the murine intestinal stem cell (ISC) system to model macroH2A’s overall ...


Elucidating The Ligand-Specific Role Of Tetraspanin12 As An Essential Co-Activator In Norrin/Frizzled4 Signaling And Retinal Vascularization, Maria B. Lai Jan 2017

Elucidating The Ligand-Specific Role Of Tetraspanin12 As An Essential Co-Activator In Norrin/Frizzled4 Signaling And Retinal Vascularization, Maria B. Lai

Molecular, Cellular, and Developmental Biology Graduate Theses & Dissertations

Genetic evidence indicates that specific combinations of accessory proteins and ligands mediate vascular Frizzled (FZD) signaling via beta-catenin in different CNS structures. Accessory proteins in FZD receptor complexes are thought to determine ligand-selectivity and signaling amplitude. In the retina, TSPAN12 is an essential co-activator in Norrin/FZD4 signaling to mediate angiogenesis. The genes encoding mediators of Norrin/FZD4 signaling are linked to familial exudative vitreoretinopathy (FEVR), an inherited retinal disease that can lead to blindness. Yet, the molecular function of TSPAN12 and the specific cell type in which TSPAN12 functions in the retina remains poorly understood. Here, I utilized binding ...


Insights Into Retinal Cell Fate Determination In Vertebrates Using Transcriptomic Profiling And Genome Editing, Rebecca Chowdhury Jan 2017

Insights Into Retinal Cell Fate Determination In Vertebrates Using Transcriptomic Profiling And Genome Editing, Rebecca Chowdhury

Graduate Theses and Dissertations

Deciphering the mechanisms of development of retinal neurons is not only of immense interest to developmental biologists, but is also vital for regenerative therapeutic applications. To attain this goal, it is critical to understand how specific intrinsic factors control cell fate decisions and neuronal maturation processes. In the retina, Atoh7 is a highly conserved transcription factor that is essential for retinal ganglion cell development in the developing mouse and zebrafish. Atoh7 labels a subset of cells in the developing retina that are progressing from a progenitor to a differentiated state. To capture cells during the window when the cell fate ...


Studies On The Molecular Underpinnings Of Sex Determination Mechanism Evolution And Molecular Sexing Tools In Turtles, Robert Alan Literman Jan 2017

Studies On The Molecular Underpinnings Of Sex Determination Mechanism Evolution And Molecular Sexing Tools In Turtles, Robert Alan Literman

Graduate Theses and Dissertations

Sex determination mechanisms (SDMs) direct the development of individuals towards a male or female fate, and in vertebrates they are typically controlled by an individual’s genotypic content (genotypic sex determination, GSD) or through an environmental cue experienced during development, mainly temperature (temperature-dependent sex determination, TSD). Among vertebrates, SDMs are surprisingly labile, transitioning between different forms of TSD and GSD in some lineages more than others. Turtles represent a model clade to study SDM evolution, as multiple independent transitions between TSD and GSD have occurred throughout their evolution and a growing number of genomic datasets have become available.

This dissertation ...


Characterizing A Signaling Network That Maintains Hematopoietic Stem Cells, Michelle Nguyen-Mccarty Jan 2017

Characterizing A Signaling Network That Maintains Hematopoietic Stem Cells, Michelle Nguyen-Mccarty

Publicly Accessible Penn Dissertations

Hematopoietic stem cells (HSCs) are able to self-renew and to differentiate into all blood cells. HSCs reside in a low-perfusion niche and depend on local signals to survive and to maintain the capacity for self-renewal. HSCs removed from the niche can survive if they receive hematopoietic cytokines, but they then lose the ability to self-renew. However, we showed previously that simultaneous inhibition of glycogen synthase kinase-3 (GSK-3) and mammalian target of rapamycin complex 1 (mTORC1) maintains HSC function ex vivo without the need for exogenous cytokines. As these experiments were initially done in heterogeneous cell populations, I then showed that ...


Functions Of Argonaute Proteins In Self Versus Non-Self Recognition In The C. Elegans Germline: A Dissertation, Meetu Seth Aug 2016

Functions Of Argonaute Proteins In Self Versus Non-Self Recognition In The C. Elegans Germline: A Dissertation, Meetu Seth

GSBS Dissertations and Theses

Organisms employ sophisticated mechanisms to silence foreign nucleic acid, such as viruses and transposons. Evidence exists for pathways that sense copy number, unpaired DNA, or aberrant RNA (e.g., dsRNA), but the mechanisms that distinguish “self” from “non-self” are not well understood. Our studies on transgene silencing in C. elegans have uncovered an RNA surveillance system in which the PIWI protein, PRG-1, uses a vast repertoire of piRNAs to recognize foreign transcripts and to initiate epigenetic silencing. Partial base pairing by piRNAs is sufficient to guide PRG-1 targeting. PRG-1 in turn recruits RdRP to synthesize perfectly matching antisense siRNAs (22G-RNAs ...


Investigating The Roles Of Δnp63 As A Suppressor Of Migration, Invasion, And Metastasis, Ramon E. Flores Gonzalez Aug 2016

Investigating The Roles Of Δnp63 As A Suppressor Of Migration, Invasion, And Metastasis, Ramon E. Flores Gonzalez

UT GSBS Dissertations and Theses (Open Access)

Cancer is one of the leading causes of death and disease in the world. Considerable resources are spent to study and understand cancer, with the hope of developing new treatments and eventually cures that will help millions of people. Efforts to understand cancer are hindered by its inherent complexity and instability. Nonetheless, understanding the basics of tumor development and progression are the key to focused on studying the role of ΔNp63 in cancer, a p53 family member known to be involved in epithelial development, microRNA biogenesis, and stem cell maintenance. Using the strength of in vivo mouse models, we found ...


Confirmation Of Emx2 Protein Binding Partners, Cody Gillman Jan 2016

Confirmation Of Emx2 Protein Binding Partners, Cody Gillman

All Master's Theses

The neocortex is a structure within mammalian brains that processes sensory input from eyes, ears, and touch receptors and mediates the conscious use of skeletal muscles. The processing of information related to each of these types of functions is localized within discrete areas of the neocortex, which are separated by sharp borders. Proper development of these functional areas is regulated during embryogenesis by several transcription factors that are expressed in distinct gradients across the progenitor layer of the neocortex, the ventricular zone. Despite the vast amount of progress that has been made in describing how these transcription factors impact the ...


Dna Repair Deficiency In Huntington's Disease Fibroblasts And Induced Pluripotent Stem Cells, Peter Anthony Mollica Oct 2015

Dna Repair Deficiency In Huntington's Disease Fibroblasts And Induced Pluripotent Stem Cells, Peter Anthony Mollica

Biological Sciences Theses & Dissertations

Mutant huntingtin protein (mhtt)– the protein responsible for cellular dysfunction in Huntington’s disease (HD) –is a product of an expanded trinucleotide repeat (TNR) cytosine-adenine-guanine (CAG) sequence in exon 1 of the huntingtin (HTT) gene. The pathology of HD has been extensively researched; however, the mechanism by which the disease-causing TNR expansions occur in somatic cells remains elusive. Interestingly, HD has often been referred to a ‘DNA repair disease’, even though DNA repair dysfunction in situ has not been identified. We hypothesized that presence of the mhtt protein affects the expression of DNA repair genes used to address DNA repair ...


Calmodulin-Like Protein 38: A Component Of Ribonucleoprotein Particles During Hypoxic Stress Responses In Arabidopsis, Ansul Lokdarshi Aug 2015

Calmodulin-Like Protein 38: A Component Of Ribonucleoprotein Particles During Hypoxic Stress Responses In Arabidopsis, Ansul Lokdarshi

Doctoral Dissertations

Waterlogging stress leads to a crisis in energy metabolism and the accumulation of toxic metabolites due to the hypoxic and/or anoxic environment associated with this condition. To respond and adapt to this situation, higher plants employ an integrated genetic program that leads to the induction of anaerobic response polypeptide genes that encode metabolic and signaling proteins involved in altering metabolic flow and other adaptive responses. The study presented here shows that the Arabidopsis thaliana calmodulin-like protein CML38 is calcium sensor protein that serves as a member of the core anaerobic response gene family and is involved in modulating the ...


Role Of Non-Muscle Myosin Ii And Calcium In Zebrafish Midbrain-Hindbrain Boundary Morphogenesis, Srishti Upasana Sahu May 2015

Role Of Non-Muscle Myosin Ii And Calcium In Zebrafish Midbrain-Hindbrain Boundary Morphogenesis, Srishti Upasana Sahu

Theses and Dissertations

Elucidating the molecular mechanisms that play a role in cellular morphogenesis is critical to our understanding of brain development and function. The midbrain-hindbrain boundary (MHB) is one of the first folds in the vertebrate embryonic brain and is highly conserved across species. We used the zebrafish MHB as a model for determining the molecular mechanisms that regulate these cell shape changes. Cellular morphogenesis is tightly regulated by signaling pathways that rearrange the cytoskeleton and produce mechanical forces that enable changes in cell and tissue morphology. The generation of force within a cell often depends on motor proteins, particularly non-muscle myosins ...


Characterization Of The Role Of Alpha-Arylphorin In The Heliothis Virescens Midgut Response To Cry1ac Toxin From Bacillus Thuringiensis, Jerreme Jamael Jackson May 2015

Characterization Of The Role Of Alpha-Arylphorin In The Heliothis Virescens Midgut Response To Cry1ac Toxin From Bacillus Thuringiensis, Jerreme Jamael Jackson

Doctoral Dissertations

Homeostasis of the intestinal epithelium in Heliothis virescens is mediated by the proliferation and differentiation of multipotent intestinal stem cells (ISCs) that lie adjacent to the basal lamina. In response to extrinsic and intrinsic signals, ISC proliferation and differentiation promotes epithelial growth and regeneration following the loss of integrity. We tested the in vivo effects of the ISC mitogen, a [alpha]-arylphorin, on ISC proliferation and the morphological changes of the midgut during larval development. Additionally, we examined how these changes affected the intestinal epithelium response to Cry1Ac toxin from Bacillus thuringiensis. Histological and in vitro evidence supported two distinct ...


Investigating Notch Signaling And Sequential Segmentation In The Fairy Shrimp, Thamnocephalus Platyurus, Sara Izzat Khalil Apr 2015

Investigating Notch Signaling And Sequential Segmentation In The Fairy Shrimp, Thamnocephalus Platyurus, Sara Izzat Khalil

Senior Theses and Projects

Segmentation is a key feature of arthropod diversity and evolution. In the standard model for arthropod development, Drosophila melanogaster, segments develop simultaneously by a progressive subdivision of the embryo. By contrast, most arthropods add segments sequentially from a posterior region called the growth zone and in a manner similar to vertebrates.

Recent work, mainly focused on insects, suggests that Notch signaling might play a role in arthropods that segment sequentially. These studies document a potential regulatory similarity between sequentially segmenting arthropods and vertebrates. In vertebrates, somite formation involves a molecular oscillator that functions as a pacemaker, driving periodic expression of ...


Deciphering Arap3 Functions In Hematopoiesis And Hematopoietic Stem Cells, Yiwen Song Jan 2015

Deciphering Arap3 Functions In Hematopoiesis And Hematopoietic Stem Cells, Yiwen Song

Publicly Accessible Penn Dissertations

ARAP3 is a GTPase-activating protein that inactivates Arf6 and RhoA GTPases. ARAP3 deficiency in mice causes a sprouting angiogenic defect resulting in embryonic lethality by E11. Mice with an ARAP3 R302,303A mutation (KI/KI) that prevents activation by PI3K have a similar angiogenic phenotype, although rare animals survive to adulthood. Although ARAP3 was first discovered in porcine leukocytes, it remains largely unstudied in hematopoiesis and hematopoietic stem cells (HSCs). In this thesis, we aim to elucidate the potential cell-autonomous and non-cell-autonomous roles of ARAP3 in hematopoiesis and HSCs using several conditional knockout (CKO) transgenic mouse models in addition to ...


Spontaneous Pancreatitis Caused By Tissue-Specific Gene Ablation Of Hhex In Mice, Mark Ferreira Jan 2015

Spontaneous Pancreatitis Caused By Tissue-Specific Gene Ablation Of Hhex In Mice, Mark Ferreira

Publicly Accessible Penn Dissertations

Background & Aims: Perturbations in pancreatic ductal bicarbonate secretion often result in chronic pancreatitis. Although the physiological mechanism of ductal secretion is known, its transcriptional control is not well characterized. Here, we investigate the role of the transcription factor Hematopoietically-expressed homeobox protein (Hhex) in pancreatic secretion and pancreatitis.

Methods: We derived mice with pancreas-specific, Cre-mediated Hhex gene ablation to determine the requirement of Hhex in the pancreatic duct in early life and in adult stages. Histological and immunostaining analyses were used to detect the presence of pathology. Pancreatic primary ductal cells (PDCs) were isolated to discover differentially expressed transcripts upon acute ...