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Full-Text Articles in Biology

The Role Of Cort And Anaphase Promoting Complex/Cyclosome (Apc/C) In Drosophila Sex Determination And Meiosis, Abuzar Sikander Malik Jan 2023

The Role Of Cort And Anaphase Promoting Complex/Cyclosome (Apc/C) In Drosophila Sex Determination And Meiosis, Abuzar Sikander Malik

Electronic Theses and Dissertations

The E3 ubiquitin ligase, APC/C, is essential for the completion cell cycle; along with its co-activators it allows mitotic exit and maintenance of G1. APC/C marks various substrates with ubiquitin chains; marked substrates are subsequently destroyed via the 26S proteasome pathway. Cort is a Drosophila female meiosis specific activator of APC/C. Cort works within meiosis in conjunction with Fzy to mediate Securin and cyclin destruction. A C-terminal IR-tail motif and a N-terminal C-box support Cort-APC/C interaction, whereas short motifs like D-box and KEN-box on the target protein impart substrate recognition to Cort. Cort expression is tightly controlled in the female …


Actin Regulation And Furrow Dynamics During Early Drosophila Embryogenesis, Yi Xie Jan 2020

Actin Regulation And Furrow Dynamics During Early Drosophila Embryogenesis, Yi Xie

Electronic Theses and Dissertations

Drosophila embryogenesis starts with a single nucleus undergo 13 rounds of nuclear divisions called syncytial cycles. Staring at cycle 10 when nuclei migrate to the surface of the embryo, massive and dynamic cortical actin structures and cleavage furrow formations occur. How actin regulators coordinate into an organized network directing three-dimension actin structures in the developing organisms is an unsolved question. Here, I present an in-depth characterization of actin cap dynamics: the actin caps go through expansion, stabilization, elongation and fragmentation phases in each cycle. Arp2/3 is the major contributor to actin cap formation. The functions of 7 different actin and …


The Role Of Dunc13 In Ethanol Tolerance, Yusuke Wachi Jan 2019

The Role Of Dunc13 In Ethanol Tolerance, Yusuke Wachi

Electronic Theses and Dissertations

Although the effects of ethanol on presynaptic activity have been studied, the molecular mechanisms and the changes in gene expression which are responsible for inducing ethanol tolerance are unclear. Munc13-1 is an active-zone protein that is essential for presynaptic vesicle fusion. This protein interacts with vesicle fusion machinery at presynaptic active zones in the mammalian brain. The C1 domain of Munc13-1 binds diacylglycerol (DAG), which helps membrane localization of this protein and promotes vesicle fusion, facilitating synaptic vesicle release. Previously, it was shown that ethanol binds to the C1 domain of Munc13-1 in vitro at concentrations below 100 mM (Das …


Autoregulation Of The Glial Gene Reversed Polarity In Drosophila Melanogaster, Jamie L. Wood Jan 2015

Autoregulation Of The Glial Gene Reversed Polarity In Drosophila Melanogaster, Jamie L. Wood

Electronic Theses and Dissertations

During development, cells of the nervous system begin as unspecified precursors and proceed along one of two developmental paths to become either neurons or glia. I seek to understand more about the genes that control this process, focusing on the lesser understood of the cell types, glial cells. Using Drosophila melanogaster as a model system, previous work from my lab and others has established the role of the master regulatory transcription factor Gcm in directing neuronal precursor cells to assume a lateral glial fate. Gcm acts on many target genes, one of which is reversed polarity (repo). repo is necessary …


Rala And Rab8 Regulate Drosophila Embryogenesis, Zhongyuan Zuo Jan 2014

Rala And Rab8 Regulate Drosophila Embryogenesis, Zhongyuan Zuo

Electronic Theses and Dissertations

Pseudocleavage furrow dynamics initiate at cycle 10 to help with mitotic divisions that lack cytokinesis. Permanent furrows then form at the beginning of cellularization (cycle 14). Cytoskeletal networks such as F-actin and non-muscle Myosin II have been demonstrated to be required for furrow formation and provide anchor points for chromosomal segregation. However, what drives the onset of furrow formation and membrane addition remains largely unclear. In my thesis, I have explored RalA and Rab8 function during furrow formation at metaphase and cellularization stages. These furrows are critical for correct chromosomal segregation, while disruption of furrow formation results in severe developmental …


Plasma Membrane Dynamics In The Drosophila Embryo, Amelia E. Zommer Jan 2011

Plasma Membrane Dynamics In The Drosophila Embryo, Amelia E. Zommer

Electronic Theses and Dissertations

Convergent extension is a highly conserved process among mammals, in which the tissue narrows in one axis, and extends across another. Tissue elongation is directed by the regulation of cell interface behaviors, which guides cell intercalation and rosette formation. Rosette formation occurs through the contraction of vertically oriented cell interfaces, and the subsequent elongation of new horizontal interfaces. It has been shown that actomyosin-generated tension functions to direct rosette formation. In this thesis, I have tested the function of regulators of F-actin networks, as well as endocytic and exocytic mechanisms, to identify new components that control interface behaviors and cell …


Notopleural Mutations Enhance Defects In Imaginal Disc Epithelial Morphogenesis And Macrochete Elongation Associated With Mutations In The Stubble-Stubbloid Locus, Robert Ruggiero Jan 2006

Notopleural Mutations Enhance Defects In Imaginal Disc Epithelial Morphogenesis And Macrochete Elongation Associated With Mutations In The Stubble-Stubbloid Locus, Robert Ruggiero

Electronic Theses and Dissertations

The Stubble-stubbloid locus encodes a transmembrane serine protease (Stubble) necessary for the proper formation of sensory bristles, and the morphogenesis of leg and wing epithelia. Genetic and cell biological analysis indicate a role for Stubble in actin cytoskeletal dynamics and cell shape changes in developing epithelia and bristles. Previously reported genetic interactions between Stubble and the Rho1 signaling pathway suggest Stubble influences actin cytoskeleton dynamics in developing imaginal discs through interactions with the Rho1 pathway. This work will discuss a genetic screen conducted to further investigate the role of Stubble in bristle and imaginal disc morphogenesis. From 50,000 EMS-mutagenized chromosomes …


Mapping And Characterization Of 18-5 And 12-5, Genes Which Potentially Link The Rhoa Signaling Pathway To The Ecdysone Response, Samuel Fox Jan 2006

Mapping And Characterization Of 18-5 And 12-5, Genes Which Potentially Link The Rhoa Signaling Pathway To The Ecdysone Response, Samuel Fox

Electronic Theses and Dissertations

Systemic steroid hormone and intracellular signaling pathways are known to act cooperatively during the development of vertebrate and invertebrate epithelia. However, the mechanism of this interaction is poorly understood. Morphogenesis of Drosophila leg imaginal disc epithelia is regulated both by the steroid hormone 20-hydroxyecdysone (ecdysone) and the RhoA GTPase signaling pathway. Recent evidence suggests that these pathways act cooperatively to control imaginal disc morphogenesis. Thus, leg imaginal disc morphogenesis is an excellent system in which to study the interaction of steroid hormone and intracellular signaling pathways. We have identified mutations in three genes, 12-5, 18-5, and 31-6, with roles in …