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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
131

Charakterizace vazby transkripčních faktorů CSL na DNA v kvasince Schizosaccharomyces pombe / Characterization of DNA binding of CSL transcription factors in fission yeast

Jordáková, Anna January 2017 (has links)
Cbf11 and Cbf12 proteins, the members of the CSL transcription factors family, are involved in a wide range of cellular processes in the fission yeast Schizosaccharomyces pombe - among other things they regulate cell adhesion and they have also been implicated in maintenance of genome integrity. At the level of the whole genome we previously identified target loci bound by CSL proteins in vivo. Many of them do not contain any consensus CSL-binding element. There are probably different DNA binding modes of the Cbf11/12 proteins and it has not been known what specific biological function is associated with the particular way of DNA binding. For the purpose of studying CSL DNA binding modes we have worked in this project on the implementation of the DNA binding mutation (DBM), which prevents direct DNA binding of CSL proteins to canonical motif in vitro, into the chromosomal locus of the cbf11 and cbf12 genes. Using the "ura4 selection system" we have successfully constructed the scar-less Cbf12-TAP and Cbf12DBM-TAP knock-ins, i.e. the strains without/with DBM in the open reading frame of Cbf12 where Cbf12 is C- terminally TAP-tagged and contains the intact 3'UTR. In our laboratory we have established the CRISPR/Cas9 system by which we have been able to prepare the Cbf11- TAP strain. We have failed to...
132

DNA vazebné vlastnosti proteinů rodiny CSL ve Schizosaccharomyces pombe / DNA-binding properties of the CSL proteins of Schizosaccharomyces pombe

Ptáčková, Martina January 2010 (has links)
As the effector component of the Notch signaling pathway the transcription factors of the CSL family (CBF1/RBP-Jκ/Suppressor of Hairless/Lag-1) are essential for many developmental processes in metazoan organisms, but they can function also independently of Notch. Recently, their presence was proved in fungal organisms lacking the Notch pathway as well as most of the known metazoan interacting partners. Cbf11 and Cbf12, the CSL proteins of the unicellular yeast Schizosaccharomyces pombe, were determined experimentally as non-essential nuclear transcription factors, which regulate cell adhesion, extracellular material production, colony morphology, septation and daughter cell separation, coordination of nuclear and cell division, and ploidy maintenance in an antagonistic way. The responsive genes of these factors are not known yet. In this study, genes of S. pombe, whose promoter regions represent potential direct targets for the Cbf proteins binding, were predicted. The binding of the Cbf11 and Cbf12 proteins, and of a truncated version Cbf12∆N to CSL response elements contained in the regulatory regions of selected S. pombe genes was tested in vitro by EMSA, and consequently, in the case of the Cbf11 protein, also in vivo by ChIP. Cbf11 and Cbf12∆N recognize specifically the response elements in...
133

Regulation of DNA Replication Origins in Fission Yeast: A Dissertation

Kommajosyula, Naveen 03 August 2009 (has links)
Cells need to complete DNA replication in a timely and error-free manner. To ensure that replication is completed efficiently and in a finite amount of time, cells regulate origin firing. To prevent any errors from being transmitted to the next generation, cells have the checkpoint mechanism. The S-phase DNA damage slows replication to allow the cell to repair the damage. The mechanism of replication slowing by the checkpoint was not clear in fission yeast, Schizosaccharomyces pombe, at the start of my thesis. The downstream targets of the DNA damage checkpoint in fission yeast were also unclear. I worked on identifying the downstream targets for the checkpoint by studying if Cdc25, a phosphatase, is a target of the checkpoint. Work from our lab has shown that origin firing is stochastic in fission yeast. Origins are also known to be inefficient. Inefficient origins firing stochastically would lead to large stretches of chromosome where no origins may fire randomly leading to long replication times, an issue called the random gap problem. However, cells do not take a long time to complete replication and the process of replication itself is efficient. I focused on understanding the mechanism by which cells complete replication and avoid the random gap problem by attempting to measure the firing efficiency of late origins. Genome-wide origin studies in fission yeast have identified several hundred origins. However, the resolution of these studies can be improved upon. I began a genome-wide origin mapping study using deep sequencing to identify origins at a greater resolution compared to the previous studies. We have extended our origin search to two other Schizosaccharomyces species- S. octosporus and S. japonicus.There have been no origin mapping studies on these fission yeasts and identifying origins in these species will advance the field of replication. My thesis research shows that Cdc25 is not a target of the S-phase DNA damage checkpoint. I showed that DNA damage checkpoint does not target Cdc2-Y15 to slow replication. Based on my preliminary observation, origin firing might be inhibited by the DNA damage checkpoint as a way to slow replication. My efforts to measure the firing efficiency of a late replicating sequence were hindered by potentially unidentified inefficient origins firing at a low rate and replicating the region being studied. Studying the origin efficiency was maybe further complicated by neighboring origins being able to passively replicate the region. To identify origins in recently sequenced Schizosaccharomyces species, we initiated the genome-wide origin mapping. The mapping was also done on S. pombe to identify inefficient origins not mapped by other mapping studies. My work shows that deep sequencing can be used to map origins in other species and provides a powerful tool for origin studies.
134

Understanding Zinc Homeostasis using Loz1 from the Fission Yeast

Wilson, Stevin January 2019 (has links)
No description available.
135

Investigation of the biophysical basis for cell organelle morphology

Mayer, Jürgen 09 February 2010 (has links) (PDF)
It is known that fission yeast Schizosaccharomyces pombe maintains its nuclear envelope during mitosis and it undergoes an interesting shape change during cell division - from a spherical via an ellipsoidal and a peanut-like to a dumb-bell shape. However, the biomechanical system behind this amazing transformation is still not understood. What we know is, that the shape must change due to forces acting on the membrane surrounding the nucleus and the microtubule based mitotic spindle is thought to play a key role. To estimate the locations and directions of the forces, the shape of the nucleus was recorded by confocal light microscopy. But such data is often inhomogeneously labeled with gaps in the boundary, making classical segmentation impractical. In order to accurately determine the shape we developed a global parametric shape description method, based on a Fourier coordinate expansion. The method implicitly assumes a closed and smooth surface. We will calculate the geometrical properties of the 2-dimensional shape and extend it to 3-dimensional properties, assuming rotational symmetry. Using a mechanical model for the lipid bilayer and the so called Helfrich-Canham free energy we want to calculate the minimum energy shape while respecting system-specific constraints to the surface and the enclosed volume. Comparing it with the observed shape leads to the forces. This provides the needed research tools to study forces based on images.
136

Investigation of the biophysical basis for cell organelle morphology

Mayer, Jürgen 12 February 2008 (has links)
It is known that fission yeast Schizosaccharomyces pombe maintains its nuclear envelope during mitosis and it undergoes an interesting shape change during cell division - from a spherical via an ellipsoidal and a peanut-like to a dumb-bell shape. However, the biomechanical system behind this amazing transformation is still not understood. What we know is, that the shape must change due to forces acting on the membrane surrounding the nucleus and the microtubule based mitotic spindle is thought to play a key role. To estimate the locations and directions of the forces, the shape of the nucleus was recorded by confocal light microscopy. But such data is often inhomogeneously labeled with gaps in the boundary, making classical segmentation impractical. In order to accurately determine the shape we developed a global parametric shape description method, based on a Fourier coordinate expansion. The method implicitly assumes a closed and smooth surface. We will calculate the geometrical properties of the 2-dimensional shape and extend it to 3-dimensional properties, assuming rotational symmetry. Using a mechanical model for the lipid bilayer and the so called Helfrich-Canham free energy we want to calculate the minimum energy shape while respecting system-specific constraints to the surface and the enclosed volume. Comparing it with the observed shape leads to the forces. This provides the needed research tools to study forces based on images.

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