Developmental Biology Commons^™

Validation Of The Activation Of Aurora B Kinase By Caenorhabditis Elegans Tousled-Like Kinase And The Identification Of Cyclin B3 As A Phospho-Specific Tlk-1 Interactor, Gary Michael Deyter

Dissertations & Theses (Open Access)

A hallmark of tumorigenesis and certain birth defect syndromes is the loss of ploidy that can result from incorrect chromosome segregation. Chromosomes that are not partitioned properly during mitosis are often fragmented, changing the genetic makeup of daughter cells. Inheriting extrachromosomal fragments that contain cell survival genes or losing chromosomal loci that encode tumor suppressors can promote tumor development. Thus, it is essential to elucidate molecular mechanisms required for correct chromosome segregation. Chromosomes are connected to mitotic spindle microtubules by way of a proteinacous, chromosome-bound organelle called the kinetochore. Two decades of research have confirmed that the conserved Aurora B/AIR-2 …

Temporal Regulation Of The Muscle Gene Cascade By Macho1 And Tbx6 Transcription Factors In Ciona Intestinalis, Jamie E. Kugler, Stefan Gazdoiu, Izumi Oda-Ishii, Yale J. Passamaneck, Albert J. Erives, Anna Di Gregorio

Dartmouth Scholarship

For over a century, muscle formation in the ascidian embryo has been representative of 'mosaic' development. The molecular basis of muscle-fate predetermination has been partly elucidated with the discovery of Macho1, a maternal zinc-finger transcription factor necessary and sufficient for primary muscle development, and of its transcriptional intermediaries Tbx6b and Tbx6c. However, the molecular mechanisms by which the maternal information is decoded by cis-regulatory modules (CRMs) associated with muscle transcription factor and structural genes, and the ways by which a seamless transition from maternal to zygotic transcription is ensured, are still mostly unclear. By combining misexpression assays with CRM analyses, …

The Ontogeny Of Muscle Structure And Locomotory Function In The Long-Finned Squid Doryteuthis Pealeii, J. T. Thompson, I. K. Bartol, A. E. Baksi, P. S. Krueger

Biological Sciences Faculty Publications

Understanding the extent to which changes in muscle form and function underlie ontogenetic changes in locomotory behaviors and performance is important in understanding the evolution of musculoskeletal systems and also the ecology of different life stages. We explored ontogenetic changes in the structure, myosin heavy chain (MHC) expression and contractile properties of the circular muscles that provide power for jet locomotion in the long-finned squid Doryteuthis pealeii. The circular muscle fibers of newly hatched paralarvae had different sizes, shapes, thick filament lengths, thin: thick filament ratio, myofilament organization and sarcoplasmic reticulum (SR) distribution than those of adults. Viewed in …

Reverse Genetic And Cell Biological Approaches To The Study Of Developmental Functions Of Class Xi Myosin In Arabidopsis Thaliana, Eunsook Park

Doctoral Dissertations

Myosin proteins function as molecular motors that drive the ATP-dependent movement of cellular components along actin filaments. Vascular plants encode two different types of myosin, referred to as class VIII and class XI. Although class XI myosins have been suggested to function in organelle movement and cytoplasmic streaming, little is known about their cellular function in detail.

The Arabidopsis genome encodes 13 class XI myosin genes. The reasons for the relatively large number of myosin XI isoforms present within a single plant species are unknown. To investigate the function of these gene products in the cell, we determined the spatial …

Very-Long-Chain Fatty Acids Are Involved In Polar Auxin Transport And Developmental Patterning In Arabidopsis, Françoise Roudier, Lionel Gissot, Frédéric Beaudoin, Richard Haslam, Louise V. Michaelson, Jessica Marion, Diana Molino, Amparo Lima, Liên Bach, Halima Morin, Frédérique Tellier, Jean-Christophe Palauqui, Yannick Bellec, Charlotte Renne, Martine Miquel, Marco Dacosta, Julien Vignard, Christine Rochat, Jennifer E. Markham, Patrick Moreau, Jonathan Napier, Jean-Denis Faure

Department of Biochemistry: Faculty Publications

Very-long-chain fatty acids (VLCFAs) are essential for many aspects of plant development and necessary for the synthesis of seed storage triacylglycerols, epicuticular waxes, and sphingolipids. Identification of the acetyl-CoA carboxylase PASTICCINO3 and the 3-hydroxy acyl-CoA dehydratase PASTICCINO2 revealed that VLCFAs are important for cell proliferation and tissue patterning. Here, we show that the immunophilin PASTICCINO1 (PAS1) is also required for VLCFA synthesis. Impairment of PAS1 function results in reduction of VLCFA levels that particularly affects the composition of sphingolipids, known to be important for cell polarity in animals. Moreover, PAS1 associates with several enzymes of …

The Cellular And Genetic Mechanisms Underlying Morphological Diversity Of Insects, Nataliya Turchyn

Wayne State University Dissertations

The vast diversity of insect appendages provides an excellent model for examining the cellular and molecular basis of phenotypic changes in nature. One of the hallmarks of evolution of insect appendages is the differential enlargement of hind (T3) legs compared to their fore (T1) and mid (T2) counterparts. While basic information regarding the genetic mechanisms that regulate the size of the T3 legs became available in the past several years, virtually nothing is known about cellular mechanisms involved. To address this issue, we measured the relative mitotic activity (RMA) in Acheta domesticus (house cricket) and Oncopeltus fasciatus (milkweed bug), two …

Unique Precursors For The Mesenchymal Cells Involved In Injury Response And Fibrosis, J. L. Walker, N. Zhai, L. Zhang, B. Bleaken, I. Wolff, Jacquelyn Gerhart, Mindy George-Weinstein, A. S. Menko

PCOM Scholarly Papers

We investigated an alternative pathway for emergence of the mesenchymal cells involved in epithelial sheet wound healing and a source of myofibroblasts that cause fibrosis. Using a mock cataract surgery model, we discovered a unique subpopulation of polyploid mesenchymal progenitors nestled in small niches among lens epithelial cells that expressed the surface antigen G8 and mRNA for the myogenic transcription factor MyoD. These cells rapidly responded to wounding of the lens epithelium with population expansion, acquisition of a mesenchymal phenotype, and migration to the wound edges where they regulate the wound response of the epithelium. These mesenchymal cells also were …

The Differential Roles Of D-Pax2 Variants In Regulating Drosophila Eye And Bristle Development, Colin J. O’Shea

Honors Theses

The ability to appropriately interact with the environment is crucial to an organism’s survival. The establishment of functional sensory systems, such as the bristles and eyes in Drosophila, is a critical event during the development of the organism. The transcription factor D Pax2 is involved in the differentiation of the shaft and glial cells in the developing bristle (Kavaler et al., Dev, 126:2261-2272, 1999) and of the cone and primary pigment cells in the developing eye (Fu and Noll, Genes Dev, 11:389-405, 1997). How D-Pax2 contributes to distinct differentiative pathways in different cell types is not known. Recent work by …

Early Cranial Patterning In The Direct-Developing Frog Eleutherodactylus Coqui Revealed Through Gene Expression, Ryan Kerney, Joshua Gross, James Hanken

Ryan Kerney

Genetic and developmental alterations associated with the evolution of amphibian direct development remain largely unexplored. Specifically, little is known of the underlying expression of skeletal regulatory genes, which may reveal early modifications to cranial ontogeny in direct-developing species. We describe expression patterns of three key skeletal regulators (runx2, sox9, and bmp4) along with the cartilage-dominant collagen 2a1 gene (col2a1) during cranial development in the direct- developing anuran, Eleutherodactylus coqui. Expression patterns of these regulators reveal transient skeletogenic anlagen that correspond to larval cartilages, but which never fully form in E. coqui. Suprarostral anlagen in the frontonasal processes are detected through …

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 …