
Gregory KellyWestern University | UWO · Department of Biology
Gregory Kelly
Ph.D.
About
83
Publications
6,153
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
1,696
Citations
Introduction
Publications
Publications (83)
Wnt and Hh are known signalling pathways involved in neural differentiation and recent work has shown the cell cycle regulator, Never in Mitosis Kinase 2 (Nek2) is able to regulate both pathways. Despite its known function in pathway regulation, few studies have explored Nek2 within embryonic development. The P19 embryonal carcinoma cell model was...
The regulation of proteins through the addition and removal of O-linked β-N-acetylglucosamine (O-GlcNAc) plays a role in many signaling events, specifically in stem cell pluripotency and the regulation of differentiation. However, these post-translational modifications have not been explored in extraembryonic endoderm (XEN) differentiation. Of the...
Metabolism plays a crucial role for cell survival and function; however, recent evidence has implicated it in regulating embryonic development. In the embryo, the inner cell mass undergoes orchestrated cellular divisions resulting in the formation of pluripotent epiblast stem cells and primitive endoderm cells. However, both lineages can be capture...
Metabolism plays a crucial role for cell survival and function; however, recent evidence has implicated it in regulating embryonic development. The inner cell mass undergoes orchestrated cellular divisions resulting in the formation of embryonic stem cells and extraembryonic endoderm (XEN) cells. Concomitantly, changes in the metabolic profile occu...
Oculodentodigital dysplasia (ODDD) is a disease caused by mutations in the GJA1 gene that encodes the gap-junctional protein connexin43 (Cx43). ODDD affects multiple organs, but craniofacial anomalies are typical. However, details on the timing of phenotypic presentation of these abnormalities and their correspondence with potential cellular change...
PARP2 belongs to a family of proteins involved in cell differentiation, DNA damage repair, cellular energy expenditure, and chromatin modeling. In addition to these overlapping functions with PARP1, PARP2 participates in spermatogenesis, T-cell maturation, extra-embryonic endoderm formation, adipogenesis, lipid metabolism, and cholesterol homeostas...
Glucose metabolism has a crucial role for providing substrates required to generate ATP and regulate the epigenetic landscape. We reported that F9 embryonal carcinoma stem-like cells require cytosolic reactive oxygen species to differentiate into extraembryonic endoderm; however, mitochondrial sources were not examined. To extend these studies, we...
PARP2 belongs to a family of proteins involved in cell differentiation, DNA damage repair, cellular energy expenditure, chromatin modeling and cell differentiation. In addition to these overlapping functions with PARP1, PARP2 participates in spermatogenesis, T-cell maturation, extraembryonic endoderm formation and adipogenesis. The function(s) of P...
INTRODUCTION
The mammalian skull develops from intramembranous and endochondral ossification. Thus, differentiation and proliferation of osteoblasts and chondrocytes play an integral role in skull development and the resulting morphology. While this connection between cellular behaviour and morphology is intuitive, the relationship between changes...
Putative GATA6 binding site in the mouse Ihh promoter.
Expression of Gata6 in response to retinoic acid. Total RNA was extracted after 24, 48, 72, and 96 h from F9 cells treated with RA to induce primitive endoderm, and then subjected to qRT-PCR using primers to Gata6. Data are representative of three independent experiments ± SEM. Letters indicate significant difference (p < 0.05) from the DMSO contro...
Cyc reduces Dkk1 expression in RA-induced F9 cells. Total RNA was extracted after 96 h from F9 cells treated with DMSO, 10−7 M RA, 10 μM Cyc, or RA and Cyc, and then subjected to qRT-PCR using primers to Dkk1. Data are representative of three independent experiments ± SEM. Letters indicate significant difference (p < 0.05) from the DMSO control and...
SAG induces the upregulation of Gli1 and Ptch2 in F9 cells. Total RNA was extracted after 24 h from F9 cells treated with DMSO or 10 nM SAG and then subjected to qRT-PCR using primers to (A)
Gli1, (B)
Ptch1, and (C)
Ptch2. Data are representative of three independent experiments ± SEM. Symbols indicate significant difference from the DMSO control a...
Oligonucleotide primer sequences used for qRT-PCR.
Mouse F9 cells differentiate into primitive extraembryonic endoderm (PrE) when treated with retinoic acid (RA), and this is accompanied by an up-regulation of Gata6. The role of the GATA6 network in PrE differentiation is known, and we have shown it directly activates Wnt6. Canonical Wnt/β-catenin signaling is required by F9 cells to differentiate...
Just over ten years have passed since the seminal Takahashi-Yamanaka paper, and while most attention nowadays is on induced, embryonic, and cancer stem cells, much of the pioneering work arose from studies with embryonal carcinoma cells (ECCs) derived from teratocarcinomas. This original work was broad in scope, but eventually led the way for us to...
Mouse F9 cells differentiate to primitive endoderm (PrE) when treated with retinoic acid (RA). Differentiation is accompanied by increased reactive oxygen species (ROS) levels, and while treating F9 cells with antioxidants attenuates differentiation, H2O2 treatment alone is sufficient to induce PrE. We identified the NADPH oxidase (NOX) complexes a...
Nox1 and Nox4 are upregulated during RA-treatment.
Total RNA was collected from F9 cells treated with DMSO or RA for 4 days. (A) Ct values for Nox1 and Nox4 under DMSO or RA treatment. (B and C) Graphical illustration of Ct values of Nox1 and Nox4 under DMSO or RA treatment over 40 cycles. L14 served as a control.
(EPS)
F9 cells show reduction in Nox1 and Nox4 expression yet maintain high oxidative state at PE.
Total RNA was collected from F9 cells induced to differentiate into PrE and PE. Expression of Nox1
(A) and Nox4
(B) following DMSO, RA, and RA with db-cAMP treatment. (C) Oxidative state of F9 cells following treatment with DMSO, RA, RA with db-cAMP. A tota...
Mouse F9 cells differentiate into primitive endoderm (PrE) following the activation of the canonical WNT–β-catenin pathway. The upregulation of Wnt6 and activation of β-catenin–TCF–LEF-dependent transcription is known to accompany differentiation, but the Frizzled (FZD) receptor responsible for transducing the WNT6 signal is not known. Eight of the...
Retinoic acid (RA) is an important signaling molecule in the development of the endoderm and an important molecule in protocols used to generate endodermal cell types from stem cells. In this review, we describe the RA signaling pathway and its role in the patterning and specification of the extra embryonic endoderm and different endodermal organs....
Retinoic acid induces mouse F9 cells to form primitive endoderm and increased levels of reactive oxygen species (ROS) accompany differentiation. ROS are obligatory for differentiation and while H2O2 alone induces primitive endoderm, antioxidants attenuate the response to retinoic acid. Evidence shows that ROS can modulate the Wnt/β-catenin pathway,...
One of the earliest epithelial-to-mesenchymal transitions in mouse embryogenesis involves the differentiation of inner cell mass cells into primitive and then into parietal endoderm. These processes can be recapitulated in vitro using F9 teratocarcinoma cells, which differentiate into primitive endoderm when treated with retinoic acid (RA) and into...
Background:
The Rho kinase pathway plays a key role in many early cell/tissue determination events that take place in embryogenesis. Rho and its downstream effector Rho kinase (ROCK) play pivotal roles in cell migration, apoptosis (membrane blebbing), cell proliferation/cell cycle, cell-cell adhesion and gene regulation. We and others have previou...
The gp91phox subunit of flavocytochrome b(558) is the catalytic core of the phagocyte plasma membrane NADPH oxidase. Its activation occurs within lipid rafts and requires translocation of four subunits to flavocytochrome b(558). gp91phox is the only glycosylated subunit of NADPH oxidase and no data exist about the structure or function of its glyca...
Embryonic development of the hemipteran Rhodnius prolixus is perturbed by fenoxycarb (Ro 13.5223, Dr. R. Maag Ltd.), a non-neurotoxic insect growth regulator. Degree of perturbation is dependent on dose applied and embryonic stage at application time. Day 5 embryos were the most sensitive over a broad dose range. Treatment on day 8 had little effec...
Heterotrimeric G proteins are involved in numerous biological processes, where they mediate signal transduction from agonist-bound G-protein-coupled receptors to a variety of intracellular effector molecules and ion channels. G proteins consist of two signaling moieties: a GTP-bound α subunit and a βγ heterodimer. The βγ dimer, recently credited as...
CASK is a member of the membrane-associated guanylate kinase family. In mammals it is an essential protein, as CASK knockout mice die after birth and its deletion in humans has developmental consequences. CASK plays a role in the transcription of genes required for forebrain development, and in the nervous systems of Drosophila and C. elegans, it p...
The mouse F9 embryonal carcinoma cell line is ideally suited to study the epithelial-to-mesenchymal transition accompanying the differentiation of primitive to parietal extraembryonic endoderm. In F9 cells, the application of exogenous agents including retinoic acid or activation of signal transduction cascades downstream of G-proteins triggers wid...
PTEN (phosphatase and tensin homologue deleted on chromosome 10) is a negative regulator of the PI3K (phosphoinositide 3-kinase)-Akt (also called protein kinase B) signalling pathway and is essential for embryogenesis, but its function in early vertebrate embryos is unclear.
To address how PTEN functions in early embryos, we overexpressed one of th...
Epithelial-to-mesenchymal transitions (EMTs) play key roles in the normal development of an organism as well as its demise following the metastasis of a malignant tumour. An EMT during early mouse development results in the differentiation of primitive endoderm into the parietal endoderm that forms part of the parietal yolk sac. In the embryo, prim...
Heterotrimeric G-protein signaling, involving alpha, beta and gamma subunits, plays a number of roles in differentiation and development. Individual gamma subunits interact with a beta subunit and as a heterodimer, is responsible for modulating many G protein-mediated cellular responses. The 12 gamma subunits in mammals have highly variable distrib...
The mouse F9 teratocarcinoma cell line is a model that can be manipulated to imitate one of the earliest epithelial-mesenchymal transitions in mouse development. When cells are treated with Retinoic Acid they differentiate into primitive endoderm and into parietal endoderm with the addition of dibutyryl cAMP. Parietal endoderm also develops when un...
Mouse F9 cells differentiate into primitive endoderm when treated with retinoic acid (RA) and into parietal endoderm in response to RA and dibutyryl (db-) cAMP. G protein signaling either blocks or mimics RA-induced differentiation, the latter signaling through the Wnt-beta-catenin pathway. In our study, we found that a constitutively active Galpha...
SHBG (sex hormone binding globulin) transports androgens and estrogens in the blood of vertebrates including fish. Orthologs of SHBG in fish are poorly defined, and we have now obtained a zebrafish SHBG cDNA and characterized the zebrafish SHBG gene and protein through molecular biological, biochemical, and informatics approaches. Amino-terminal an...
Although Xenopus studies have shown that Frizzled 7 activates at least two noncanonical signaling pathways, it is less clear which, if any, of these signaling pathways are downstream of Frizzled 7 in zebrafish. Cotransfection of Frizzled 7a (Fz7a) or Frizzled 7 (Fz7) and Xenopus Dsh-GFP results in the translocation of Dsh from the cytoplasm to the...
Cellular processes rely on dynamic events occurring between the cortical cytoskeleton and plasma membrane. Members of the Band 4.1 superfamily, which are best known for their ability to tether the cytoskeleton to the plasma membrane, play prominent structural and regulatory roles that influence cell-cell and cell-substrate interactions, endo- and e...
G proteins play an essential role in the transduction and propagation of extracellular signals across the plasma membrane. It was once thought that the G protein α subunit was the sole regulator of intracellular molecules. The G protein βγ complex is now recognized as participating in many signaling events. While screening a zebrafish cDNA library...
Ran, which functions in nucleocytoplasmic transport and mitosis, binds to and is regulated in part by RanBP1. We have identified a zebrafish RanBP1 cDNA and report that it encodes for a polypeptide of 233 amino acids with considerable similarity to human and XenopusRanBP1, despite the fact that it is 10% longer due to an extension at its carboxy te...
G proteins play an essential role in the transduction and propagation of extracellular signals across the plasma membrane. It was once thought that the G protein α subunit was the sole regulator of intracellular molecules. The G protein βγ complex is now recognized as participating in many signaling events. While screening a zebrafish cDNA library...
The normal translocation of nascent polypeptides into the lumen of the endoplasmic reticulum (ER) is thought to be aided in part by a translocon-associated protein (TRAP) complex consisting of 4 protein subunits. The association of mature proteins with the ER and Golgi, or other intracellular locales, such as lysosomes, depends on the initial targe...
Heterotrimeric G proteins are involved in numerous biological processes, where they mediate signal transduction from agonist-bound G-protein-coupled receptors to a variety of intracellular effector molecules and ion channels. G proteins consist of two signaling moieties: a GTP-bound alpha subunit and a beta-gamma heterodimer. The beta-gamma dimer,...
The zebrafish has long been the favorite organism in many scientific disciplines. Although its attributes as a model were expounded for many years and thus were no secret, the zebrafish sat in the wings while other more popular vertebrates such as chick, amphibians, and mouse were examined at length. We cannot say there was a resurgence in populari...
Membrane skeleton protein 4.1 and other members of a family of proteins that link the cytoskeleton to the plasma membrane may play an integral role in cell communication during development. The polymerase chain reaction and degenerate oligodeoxynucleotide primers to consensus sequences in the putative membrane-binding domain of the protein 4.1 supe...
We previously used 2-dimensional (2-D) gel electrophoresis to identify novel proteins that may be involved in the genesis of the mammalian nervous system [1]. Several novel proteins that were up- or down-regulated coincident with neurogenesis and neuronal migration in rat neocortex were identified. To further investigate the expression of some of t...
Hsp47 is a major stress-inducible protein that is localized to the endoplasmic reticulum of avian and mammalian cells and is thought to act as a molecular chaperone specific for the processing of procollagen. Although hsp47 is coordinately expressed together with several collagen types, and vertebrate embryos are known to express collagen genes in...
Formation of the vertebrate axis may involve a Wnt signaling cascade similar to the Drosophila wingless pathway. Zebrafish wnt8 is a candidate for involvement in axis specification insofar as it is expressed maternally and when overexpressed it can induce goosecoid, a transcription factor normally expressed in the embryonic shield. In this study we...
The Wnts are a family of secreted glycoproteins involved in cell-cell signalling and pattern formation during development, although the extent to which various Wnts are functionally equivalent remains unclear. We have cloned zebrafish (Danio rerio) wnt4, characterized its expression, and compared its activity relative to other Wnts. The wnt4 transc...
The specification of the vertebrate body plan is dependent on numerous signaling molecules, including members of the Wnt family. We have identified two zebrafish wnt8 paralogs related to Xwnt-8B and Xwnt-8, respectively. A RT-PCR assay demonstrated that wnt8 is expressed maternally, with transcripts detected throughout embryogenesis, whereas wnt8b...
The secreted signalling molecule encoded by the wnt1 gene and the paired box-containing pax2 gene are thought to play an integral role in patterning the zebrafish rostral nervous system. Using a double-label analysis, we compare the expression patterns of wnt1 RNA and pax2 protein during zebrafish embryogenesis to determine whether they were expres...
On Jun 28, 2001 this sequence version replaced gi:968914.
A polymerase chain reaction-derived clone with sequence homology to partial-length shark and salamander Wnt-10a was used to screen a zebrafish cDNA library, yielding a cDNA encoding a full-length Wnt polypeptide. Transcripts encoding zebrafish wnt10a are first detected during the segmentation period of embryogenesis, at a time when there is extensi...
We review evidence that Xenopus Wnts (Xwnts) have activities consistent with their hypothesized roles as secreted signalling factors involved in multiple developmental processes. Transient misexpression of different Xwnts has distinct effects upon early development, and upon the formation of tissues in UV-irradiated embryos. Misexpression of Xwnts...
Cellular shape change and the motility of embryonic cells are brought about primarily by two filament systems, the microtubules and microfilaments. Intermediate filaments comprise a complex multigene family of more than 30 unique proteins, all of which have the capacity to assemble into 8-10 nm filaments. Individual proteins are expressed in a deve...
Xenopus membrane skeleton protein 4.1 is expressed constitutively during embryonic development and accumulates to high levels within the retina during normal morphogenesis. There exists a high degree of amino acid identity between Xenopus protein 4.1 and human protein 4.1, suggesting that the mechanisms known to modulate the function(s) of human pr...
This chapter outlines the techniques that are used successfully in laboratory to examine morphologically oogenesis and particularly embryogenesis under normal and experimental conditions. Modified Karnovsky fixative containing dimethyl sulfoxide (DMSO) is ideal for preserving Xenopus tissue for transmission (TEM) and scanning electron microscopy (S...
Membrane skeleton protein 4.1 plays a key role in modulating the interactions of spectrin, actin, and integral membrane proteins in erythroid and nonerythroid cells. We have investigated its structure and expression during embryonic development of Xenopus laevis. An analysis of the complete 2758-nucleotide sequence and predicted translation of 801...
The embryonic development of the hemipteran insect Rhodnius prolixus was studied by use of contemporary light and electron microscopy. Embryos were staged according to days postoviposition. Eggs laid on day one complete blastoderm formation and anatrepsis, the first phase of blastokinesis, by day 5. The embryo develops in a cephalocaudal orientatio...
Protein electrophoretic techniques demonstrate that the normal patterns of protein synthesis accompanying embryogenesis of Rhodnius prolixus are altered by the juvenoid compound Ro 13.5223 (fenoxycarb). Electrophoretic analysis reveals that embryonic perturbation by fenoxycarb is due in part to alterations in the normal molecular events accompanyin...