Cell and Developmental Biology Commons^™

Investigating The Role Of Lbh During Early Embryonic Development In Xenopus Laevis, Emma Weir

Masters Theses

LBH is a highly conserved protein whose role during vertebrate development is relatively under-studied. In collaboration with the Albertson lab, our lab has previously shown that it is necessary for cranial neural crest cell migration in the zebrafish and in Xenopus laevis. The molecular mechanisms through which it acts are not well understood.

In Xenopus, LBH is a maternally deposited protein. As such, studying its role in early development has not been feasible through the morpholino-mediated knockdown techniques that prevent translation of target genes. Recently, a technique for degrading endogenous proteins was developed, called Trim-Away. This was developed in mammalian …

The Role Of Hand1 In The Development Of The Lateral Plate Mesoderm In Xenopus, Victoria A. Deveau

Electronic Thesis and Dissertation Repository

The transcription factor hand1 is expressed in the heart, lateral plate mesoderm (LPM) and neural crest cells during development. As Hand1-null mice die early in embryogenesis, identification of the precise role of Hand1 in development is difficult. In Xenopus, we observed that hand1 expression patterns correlates very closely with development of LPM derivatives, leading us to hypothesize that hand1 is required for normal LPM development. Using hand1 knockdown and overexpression models in Xenopus, development of LPM derivatives were assessed by whole mount in situ hybridization. I found that hand1 is required for proper heart morphogenesis. Furthermore, hand1 …

The Role Of Pitx Proteins In Early Xenopus Development, Ye Jin

Dissertations, Theses, and Capstone Projects

Embryos of the African clawed frog Xenopus laevis are widely used for the study of early vertebrate development. The cement gland, which secrets mucus to help tadpoles attach to solid supports and live in relative safety, has long been used as a model to study the interplay between cell signaling pathways and transcription factors. It has been proposed that an intermediate level of Bone Morphogenetic Protein (BMP) signaling is essential for cement gland formation. In addition, several transcription factors have been linked to cement gland development. Among them, the homeodomain proteins Pitx1 and the closely related Pitx2c can generate ectopic …

Development Of Mechanosensory Innervation In The Frog, Xenopus Laevis, Peter Andrew Feuk

Theses and Dissertations

ABSTRACT

DEVELOPMENT OF MECHANOSENSORY INNERVATION IN THE FROG, XENOPUS LAEVIS

by

Peter Feuk

The University of Wisconsin-Milwaukee, 2017

Under the Supervision of Dr. R. David Heathcote

This study aims to investigate whether a specific target cell in the epidermis of the African clawed frog, Xenopus laevis, guides the initial outgrowth and pattern of Rohon-Beard (RB) cells and their survival. RB cells are primary mechanosensory neurons present during the early developmental stages of X. laevis. These neurons provide sensory input to the frog throughout embryonic and larval development before initiating apoptosis around the start of metamorphosis. The innervation of embryonic skin …

Identification Of Size And Shape Changes In Orofacial Development And Disease, Allyson E. Kennedy

Theses and Dissertations

Among the most prevalent and devastating types of human birth defects are those affecting the mouth and face, such as orofacial clefts. Children with malformed orofacial structures undergo multiple surgeries throughout their lifetime and struggle with facial disfigurements, speech, hearing, and eating problems. Therefore, facilitating new research in cranio- and orofacial development is paramount to prevention and treatment of these types of birth defects in humans. Xenopus laevis has emerged as a new tool for dissecting the mechanisms governing facial development. Thus, molecular analyses accompanied by quantitative assessment of morphological changes during orofacial development of this species could be very …

Developmental And Molecular Functions Of Plakophilin-3, William A. Munoz

Dissertations & Theses (Open Access)

Plakophilin-3, the less studied member of the plakophilin-catenin subfamily, and the larger catenin family, binds directly to desmosomal cadherin cytoplasmic domains and enhances desmosome formation and stability. In mammals, plakophilin-3 is expressed at the highest levels in desmosome-enriched tissues such as epithelia, with the knock-out in mice producing corresponding reductions in ectodermal integrity. In tissue, cellular and intracellular contexts where plakophilin-3 is not at the desmosomal plaque, little is known about its functions in the cytoplasm or nucleus, where it also localizes.

My work employed embryos of the amphibian, Xenopus laevis, to examine plakophilin-3’s developmental roles. I first evaluated …

Post-Translational Modification Regulates Heterogeneous Nuclear Ribonucleoprotein K Function During Axon Outgrowth In Xenopus Laevis, Erica J. Hutchins

Legacy Theses & Dissertations (2009 - 2024)

The RNA-binding protein, heterogeneous nuclear ribonucleoprotein K (hnRNP K), is required for axon outgrowth. Its suppression in Xenopus embryos causes defects in the translation of mRNAs of multiple cytoskeletal genes. Studies in cell lines have established that hnRNP K shuttles between the nucleus and the cytoplasm to bind and regulate the fates of its target RNAs, from splicing to export and translation. At each step, hnRNP K is regulated through post-translational modifications that alter its nucleic acid and protein interactions, and subcellular localization. Precisely how this happens in developing neurons to coordinate cytoskeletal gene expression with the extracellular signals directing …

Regulatory Elements Of Xenopus Col2a1 Drive Cartilaginous Gene Expression In Transgenic Frogs, Ryan Kerney, Brian K. Hall, James Hanken

Ryan Kerney

This study characterizes regulatory elements of collagen 2α1 (col2a1) in Xenopus that enable transgene expression in cartilage-forming chondrocytes. The reporters described in this study drive strong cartilage-specific gene expression, which will be a valuable tool for further investigations of Xenopus skeletal development. While endogenous col2a1 mRNA is expressed in many embryonic tissues, its expression becomes restricted to tadpole and adult chondrocytes. This chondrocyte-specific expression is recapitulated by col2a1 reporter constructs, which were tested through I-SceI meganuclease-mediated transgenesis. These constructs contain a portion of the Xenopus tropicalis col2a1 intron, which aligns to a cartilage-specific intronic enhancer that has been well characterized …

Skeletal Advance And Arrest In Giant Non-Metamorphosing African Clawed Frog Tadpoles (Xenopus Laevis: Daudin), Ryan Kerney, Richard Wassersug, Brian Hall

Ryan Kerney

This study examines the skeletons of giant non-metamorphosing (GNM) Xenopus laevis tadpoles, which arrest their development indefinitely before metamorphosis, and grow to excessively large sizes in the absence of detectable thyroid glands. Cartilage growth is isometric; however, chondrocyte size is smaller in GNM tadpoles than in controls. Most cartilages stain weakly with alcian blue, and several cartilages are calcified (unlike con- trols). However, cartilages subjacent to periosteum-derived bone retain strong affinities for alcian blue, indicat- ing a role for periosteum-derived bone in the retention of glycosaminoglycans during protracted larval growth. Bone formation in the head, limb, and axial skeletons is …

The Biology Of Xenopus By R. C. Tinsley And H. C. Kobel, Rafael O. De Sá

Biology Faculty Publications

The Biology of Xenopus presents a summary of current knowledge about a single genus resulting from a symposium held at the Zoological Society of London in September 1992. This approach to summarizing available information has also been taken for other taxa, such as Atelopus (Lotters, 1996). However, the task of compiling data for Xenopus is enormous relative to any other amphibian group, because Xenopus laevis has become a model system for molecular and development research (Cannatella and de Sa, 1993). Unfortunately, most of our knowledge of Xenopus is biased toward this single species. There are about 20 recognized species of …

Xenopus Laevis As A Model Organism, David C. Cannatella, Rafael O. De Sá

Biology Faculty Publications

Model organisms are often assumed to be representative of some more inclusive taxon of which the species is a part. This assumption leads to mistaken generalizations about the evolutionary and comparative significance of the data gathered. This paper reviews com? parative and evolutionary studies of Xenopus laevis and its relatives. Phylogenetic analysis of data from DNA sequences and morphology indicate that Xenopus is monophyletic and that Silurana is its sister group. The most basal lineages of Pipidae diverged prior to the breakup of Gondwana. The bizarre morphology of Xenopus is in part due to changes in the mode of meta? …