|
| |
|
| |
|
|
Promyelocytic leukemia protein function in normal, tumor and senescent human cells
Rossmeislová, Lenka ; Hozák, Pavel (advisor) ; Forstová, Jitka (referee) ; Anděra, Ladislav (referee)
Promyelocytic leukemia protein (PML) gene encodes a nuclear protein localizing into the nucleoplasm and distinct nuclear bodies, referred to as PML nuclear bodies (PML NBs). PML is now considered as a gene with tumor-suppressive properties since it is implicated in many nuclear functions affecting cellular proliferation, apoptosis and senescence. The presented work is a part of a larger project that aims to clarify the regulation of promyelocytic leukemia protein expression and investigates the role of PML protein in cellular senescence. The specific goals of my PhD project were to evaluate new in vitro models for the study of PML, to elucidate the effects of histone deacetylase inhibitors on PML gene expression, and to investigate the association of PML with the nucleolus.
|
|
|
Studies of minor capsid proteins of the mouse polyomavirus
Vít, Ondřej ; Němečková, Šárka (referee) ; Forstová, Jitka (advisor)
Mouse polyomavirus (MPyV) is a small non-enveloped virus. Its capsid consists of 72 pentamers of the major capsid protein VP1. The central cavity of each VP1 pentamer contains one minor capsid protein, either VP2, or VP3. The minor capsid proteins are dispensable for capsid formation, but their presence is required for infection of the host cell, presumably because of their anticipated functions during virus entry. After internalization, MPyV virions traffic to endoplasmic reticulum (ER). VP2 and VP3 have been proposed to function as factors responsible for penetration of ER membranes, which is required for subsequent delivery of the viral DNA into the nucleus, a key step of the early phase of MPyV infection. Three hydrophobic domains were predicted in the sequence of VP2 and VP3. First in the unique Nterminal part of VP2, second and third in the common part of VP2 and VP3. The third domain corresponds to C-terminal VP1binding alpha-helix. It has been previously found in our laboratory, that VP2 and VP3 fused to N-terminus of EGFP, when expressed in mammalian cells, display properties similiar to the wild-type VP2 and VP3, namely affinity to intracellular membranes and high cytotoxicity. Expression plasmids carrying mutated VP2 and VP3 fused to Nterminus of EGFP were prepared to determine the hydrophobic...
|
|
|
Caveolae and caveosoms
Galica, Tomáš ; Forstová, Jitka (referee) ; Černý, Jan (advisor)
Caevolae are remarkably stable structures at the plasma membrane. They form specific domains distinct in lipid composition from the rest of plasma membrane. Many diverse functions are assigned to Caevolae. They play role in modulation of cellular surface, signalization and well regulated endocytosis. Caveosomes suppose to be large intracellular vesicular structures potentialy new membrane organels. They are derived from internalized caveolae. Tohether with caveolae they are proposed to form a separeted system of intracellular vesicles. However recent evidence suggests that caveolae can fuse with endosomes immediately after internalization. If this is true, then the system of vesicles derived from caveolae, including caveosomes, can be considered a regular component of endosomal system. Isolation of caveosomes from endosomes has been seen mainly in experiments where polyomavirus SV40 was used. Thus the question, if this isolation is not just a result of SV40 infection, arises. It has been shown recently that SV40 virus is capable of inducing caveosome-like structures even in the absence of caveolae. Consequently existence and properties of caveosomes are being questioned. The problem of high importance is the genesis of caveosomes and their existence in SV40 non-infected cells. In this thesis...
|
|
|
Study of the assembly and budding of mouse mammary tumor virus MMTV
Hoboth, Peter ; Zábranský, Aleš (advisor) ; Forstová, Jitka (referee)
Mouse mammary tumor virus (MMTV) is a prototypical member of the Betaretrovirus genus characterized by the ability to preassemble viral particles in the cytoplasm of the host cells. Intracellularly preassembled particles are subsequently transported to the plasma membrane being enveloped by a lipid bilayer and released from the cell in the process referred to as budding. Retrovirus particle assembly is driven by the Gag polyprotein precursor, which is cleaved in the maturation process by virus-encoded protease to liberate multiple structural proteins. The matrix (MA), capsid (CA) and nucleocapsid (NC) protein domains that are common to all retroviruses and in the case of MMTV, also the noncanonical domains, pp21, p3, p8 and "n", located between MA and CA domain are present. The role of these specific domains remains undefined. The retroviral budding is stimulated by short peptide motifs, so-called late (L) domains, located within Gag sequence. These L domains mediate interactions with cellular proteins normally involved in the biogenesis of the multivesicular bodies and protein sorting. Three types of the L domains have been identified to date, with the consensus of the amino acid sequences (i) P(T/S)AP, (ii) YP(x)nL (where x represents any amino acid and n≤3) and (iii) PPxY. Disruption of the L domain...
|
|
| |
|
| |
|
|
Optical microscopy to study the role of cytoskeleton in cell locomotion and virus trafficking
Difato, Francesco ; Forstová, Jitka (advisor) ; Hozák, Pavel (referee) ; Plášek, Jaromír (referee)
3. General conclusions 150 The interest in optical microscopy is constanly growing, mainly because of its unique features in examining biological systems in four dimensions (x-y-z-t)1 . The work presented here was focused on biological applications of optical microscopy by exploring and improving the spatial and temporal resolution performances and by futher developing optical tools for manipulating biological samples. First, I studied the resolution performances of the system in the three dimensional space and I contributed in improving the experimental spatial resolution of microscope by applying deconvolution. In this respect, theoretical modelling can characterize the image formation process of the microscope, but only experimental measurement of the PSF can quantify the limitations of the real system. Indeed, experimental PSF presents shape assymetry due to spherical aberrations introduced by optical elements, while theoretical PSF is symmetric and account only for the resolution limits of an ideal imaging system. The disadvantage of experimental PSF is that could be corrupted by noise, otherwise deconvolution with the theoretical PSF offer only a qualitative improvement of the image, because the introduced artefacts cannot be quantified. Deconvolution of the acquired data with experimental PSF...
|
|
| |
guest ::
RSS feed.