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The mechanism of impaired formation of head-tail coupling apparatus in centrobin deficient acephalic spermatozoa
Vlčková, Monika ; Frolíková, Michaela (advisor) ; Krejčová, Tereza (referee)
Acephalic sperm syndrome (ASS) is a rare form of teratozoospermia that is probably genetic in origin. The sperm of individuals with this syndrome have a damaged apparatus connecting the head and flagellum (HTCA), which leads to the formation of acephalic sperm, i.e. sperm with separate heads from flagella. Individuals affected by ASS are almost exclusively infertile. One of the proteins whose mutation causes ASS is SUN5. Together with KASH proteins, SUN proteins are part of the so-called LINC complex, which ensures the connection of the nucleoskeleton with the cytoskeleton. Centrobin is a protein involved in centriole duplication and assembly of the dividing spindle. Rats carrying a defective gene for centrobin have reduced fertility and exhibit an ASS phenotype. For that reason, this model organism was used in this work to study the possible interrelationships of proteins involved in the formation of ASS. Given the similar phenotype of centrobin and SUN5 mutated spermatozoa, there is a possibility that centrobin interacts with one of the LINC complex proteins and together they participate in the formation of the head-flagella junction. Sperm from rats with a defective centrobin gene also show significant damage to the flagella. Decreased Odf1 protein expression has previously been reported in ASS...
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Viruses and cytosketelon of the cell nucleus
Cibulka, Jakub ; Forstová, Jitka (advisor) ; Šťovíček, Vratislav (referee)
The nuclear cytoskeleton (the nucleoskeleton) provides a structural integrity to the nucleus and is involved in number of key processes including transcription, chromatin remodelling and mRNA transport. The nucleoskeleton consists of nuclear lamins, nuclear actin and other proteins. Some viruses, which replicate themselves in the nucleus, use nuclear cytoskeleton in their life-cycle. On the other hand the nucleosketon may also represent a barrier for viral infection. Herpesviruses need nuclear actin for capsid assembly and transport, but they have to desintegrate the nuclear lamina in order to escape the nucleus. Nuclear actin also participates in the morphogenesis and probably nuclear export of baculovirus capsids. Some retroviruses transport their unspliced RNAs from the nucleus using nuclear actin and there is also some evidence of retrovirus-induced nuclear lamina disruption. In this work, I focus on the interactions of above-mentioned viruses with the nuclear cytoskeleton (namely nuclear actin and lamins).
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Localization matters: function of paxillin and phopholipids in the cell nucleus
Marášek, Pavel ; Hozák, Pavel (advisor) ; Půta, František (referee) ; Žárský, Viktor (referee)
(English) Both paxillin and PIP2 are well known components of the cell, although of a distinct origin. Focal adhesion protein paxillin spreads the signals from extracellular matrix via integrins and growth factor receptors to affect cellular motility and migration (Schaller, 2001). PIP2, a major structural component of cytoplasmic membrane, is utilized by phospholipase C to generate second messenger molecules (Hokin and Hokin 1953; Streb et al. 1983). Both molecules were recently shown to be localized in the nucleus. Their original functions have been well established, but together with other research colleagues we are now shedding more light on completely different functions of these biological molecules and moreover, in the different compartments than they were primarily believed to function in. Here, we introduce paxillin as an important factor of the cell nucleus, where it regulates transcription of two important growth-related genes, IGF2 and H19. It does not affect the allelic expression of these imprinted genes, it rather regulates long-range chromosomal interactions between H19 or IGF2 promoter, and the shared distal enhacer on an active allele. In detail, paxillin stimulates the interaction between the enhancer and the IGF2 promoter, activating IGF2 gene transcription, while it restrains...
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Localization matters: function of paxillin and phopholipids in the cell nucleus
Marášek, Pavel ; Hozák, Pavel (advisor) ; Půta, František (referee) ; Žárský, Viktor (referee)
(English) Both paxillin and PIP2 are well known components of the cell, although of a distinct origin. Focal adhesion protein paxillin spreads the signals from extracellular matrix via integrins and growth factor receptors to affect cellular motility and migration (Schaller, 2001). PIP2, a major structural component of cytoplasmic membrane, is utilized by phospholipase C to generate second messenger molecules (Hokin and Hokin 1953; Streb et al. 1983). Both molecules were recently shown to be localized in the nucleus. Their original functions have been well established, but together with other research colleagues we are now shedding more light on completely different functions of these biological molecules and moreover, in the different compartments than they were primarily believed to function in. Here, we introduce paxillin as an important factor of the cell nucleus, where it regulates transcription of two important growth-related genes, IGF2 and H19. It does not affect the allelic expression of these imprinted genes, it rather regulates long-range chromosomal interactions between H19 or IGF2 promoter, and the shared distal enhacer on an active allele. In detail, paxillin stimulates the interaction between the enhancer and the IGF2 promoter, activating IGF2 gene transcription, while it restrains...
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Viruses and cytosketelon of the cell nucleus
Cibulka, Jakub ; Forstová, Jitka (advisor) ; Šťovíček, Vratislav (referee)
The nuclear cytoskeleton (the nucleoskeleton) provides a structural integrity to the nucleus and is involved in number of key processes including transcription, chromatin remodelling and mRNA transport. The nucleoskeleton consists of nuclear lamins, nuclear actin and other proteins. Some viruses, which replicate themselves in the nucleus, use nuclear cytoskeleton in their life-cycle. On the other hand the nucleosketon may also represent a barrier for viral infection. Herpesviruses need nuclear actin for capsid assembly and transport, but they have to desintegrate the nuclear lamina in order to escape the nucleus. Nuclear actin also participates in the morphogenesis and probably nuclear export of baculovirus capsids. Some retroviruses transport their unspliced RNAs from the nucleus using nuclear actin and there is also some evidence of retrovirus-induced nuclear lamina disruption. In this work, I focus on the interactions of above-mentioned viruses with the nuclear cytoskeleton (namely nuclear actin and lamins).
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