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Factors important for Cajal body formation
Roithová, Adriana ; Staněk, David (advisor) ; Valentová, Anna (referee)
This research describes the structure and function of nuclear domains called Cajal bodies (CB). CB contain proteins and factors involved in assembly and modification of snRNPs. These bodies are found in vertebrates and invertebrates and even plants. Not all cell types contain CB. Their number and size depends on the transcription activity of cell and cell cycle phase. This paper discusses the factors that affect the CB formation. One of the most important factors is the level of snRNPs and transcription activity. Recently shows that an important role in CB formation has coilin and other components phosphorylation. Other works show the influence of the environment. There is also discussion regulation of CB biogenesis, witch is not yet fully understood. Key words: Cajal bodies, coilin, cell nucleus, snRNP, pre-mRNA splicing, transcription
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Defects in DNA repair and RNA metabolism associated with human neurological disorders
Cihlářová, Zuzana ; Hanzlíková, Hana (advisor) ; Čermák, Lukáš (referee) ; Roithová, Adriana (referee)
The human genome is constantly under the attack by various damaging agents, leading to the breakage of one or both strands of DNA that might interfere with RNA processing. Importantly, our cells have evolved diverse mechanisms to rapidly repair various DNA lesions, highlighting the importance of genetic integrity. Defects in DNA repair and/or RNA metabolism can lead to a variety of human hereditary diseases, with pathologies including growth and developmental defects, immunodeficiency, predisposition to cancer, and neurodegeneration. Mutations in the BRAT1 (BRCA1-associated ATM activator-1) protein have been associated with neurological disorders characterized by heterogenous phenotypes with varying levels of clinical severity ranging from microcephaly, hypertonia, epilepsy, seizures, and early death in the first two years of life to mild cerebellar atrophy and ataxia. Previously, BRAT1 protein has been implicated in the cellular response to DNA double-strand breaks and ATM signalling. However, the exact mechanism/s by which mutations in BRAT1 gene trigger neurological disorders are largely unknown. Recently, we have identified a homozygous missense c.185T>A (p.Val62Glu) variant in BRAT1 that markedly reduced the level of BRAT1 protein in patient-derived cell lines. Surprisingly, our data show that...
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Quality control in snRNP biogenesis
Roithová, Adriana ; Staněk, David (advisor) ; Malínský, Jan (referee) ; Vomastek, Tomáš (referee)
(English) snRNPs are key components of the spliceosome. During their life, they are found in the cytoplasm and also in the nucleus, where carry out their function. There are five major snRNPs named according to RNA they contain U1, U2, U4, U5 and U6. Each snRNP consists from RNA, ring of seven Sm or LSm proteins and additional proteins specific for each snRNP. Their biogenesis starts in the nucleus, where they are transcribed. Then they are transported into the cytoplasm. During their cytoplasmic phase, the SMN complex forms the Sm ring around the specific sequence on snRNA and cap is trimethylated. These two modifications are the signals for reimport of snRNA into the nucleus, where they accumulate in the nuclear structures called Cajal bodies (CBs), where the final maturation steps occur. There are several quality control points during snRNP biogenesis that ensure that only fully assembled particles reach the spliceosome. The first checkpoint is in the nucleus immediately after the transcription, when the export complex is formed. The second checkpoint is in the cytoplasm and proofreads Sm ring assembly. If the Sm ring formation fails, the defective snRNPs are degraded in the cytoplasm by Xrn1 exonuclease. However, it is still unclear, how the cell distinguishes between normal and defective...
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Quality control in snRNP biogenesis
Roithová, Adriana ; Staněk, David (advisor) ; Malínský, Jan (referee) ; Vomastek, Tomáš (referee)
(English) snRNPs are key components of the spliceosome. During their life, they are found in the cytoplasm and also in the nucleus, where carry out their function. There are five major snRNPs named according to RNA they contain U1, U2, U4, U5 and U6. Each snRNP consists from RNA, ring of seven Sm or LSm proteins and additional proteins specific for each snRNP. Their biogenesis starts in the nucleus, where they are transcribed. Then they are transported into the cytoplasm. During their cytoplasmic phase, the SMN complex forms the Sm ring around the specific sequence on snRNA and cap is trimethylated. These two modifications are the signals for reimport of snRNA into the nucleus, where they accumulate in the nuclear structures called Cajal bodies (CBs), where the final maturation steps occur. There are several quality control points during snRNP biogenesis that ensure that only fully assembled particles reach the spliceosome. The first checkpoint is in the nucleus immediately after the transcription, when the export complex is formed. The second checkpoint is in the cytoplasm and proofreads Sm ring assembly. If the Sm ring formation fails, the defective snRNPs are degraded in the cytoplasm by Xrn1 exonuclease. However, it is still unclear, how the cell distinguishes between normal and defective...
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Inhibitors of the eukaryotic translation initiation factor eIF4E1
Pospíšilová, Klára ; Pospíšek, Martin (advisor) ; Roithová, Adriana (referee)
Protein synthesis is one of the most important processes that take place in a cell. Thus there are various mechanisms in a cell that regulate it. If that regulation fails it may lead to serious pathologies. An example of this is an abnormal increase in the production of eukaryotic translation initiation factor 4E1 which occurs in some types of cancer including head and neck squamous cell carcinoma, colorectal cancer, cervical cancer or lung cancer. Enhanced availability of factor 4E1 enables transformed cells to undertake a more intense translation. The expression of individual proteins is not increased to the same extent though. The enhancement in the level of factor 4E1 has a more significant effect on oncogenic proteins. Malignant transformation caused by an incorrect regulation of factor 4E1 can be precluded by an application of compounds that impair the activity of factor 4E1. A summarization of 4E1 inhibitors is the subject of this work.
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U2 snRNA targeting to Cajal bodies
Roithová, Adriana ; Staněk, David (advisor) ; Mašek, Tomáš (referee)
In the cell we can find a lot of small noncoding RNAs, which are important for many processes. Among those RNAs are small nuclear RNA uridin rich, which with proteins create U snRNP.These particles play important role in pre-mRNA splicing. In this process are noncoding sequences (introns) removed and coding sequences (exons) are joined. It is catalyzed by spliceosome. The core of this spliceosome is created by U1, U2, U4, U5 and U6 snRNP. They are essential for this process. Some steps of U snRNP biogenesis proceed in nuclear structures called Cajal bodies (CB). In my thesis I focused on factors, which are important for targeting U snRNA into CB. I used U2 snRNA like a model. With the aid of microinjection of fluorescently labeled U2 snRNA mutants I found, that the Sm binding site on U2 snRNA is essential for targeting to CB. Knock down of Sm B/B'showed us, that Sm proteins are necessary for transport U2 snRNA to CB. Sm proteins are formed on U2 snRNA by SMN complex. Deletion of SMN binding site on U2 snRNA had the same inhibition effect. From these results we can see, that Sm proteins and SMN complex are important for U2 snRNA biogenesis espacially for targeting into CB. Key words: U snRNP, Cajal body, U snRNA, cell nucleus
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Factors important for Cajal body formation
Roithová, Adriana ; Staněk, David (advisor) ; Valentová, Anna (referee)
This research describes the structure and function of nuclear domains called Cajal bodies (CB). CB contain proteins and factors involved in assembly and modification of snRNPs. These bodies are found in vertebrates and invertebrates and even plants. Not all cell types contain CB. Their number and size depends on the transcription activity of cell and cell cycle phase. This paper discusses the factors that affect the CB formation. One of the most important factors is the level of snRNPs and transcription activity. Recently shows that an important role in CB formation has coilin and other components phosphorylation. Other works show the influence of the environment. There is also discussion regulation of CB biogenesis, witch is not yet fully understood. Key words: Cajal bodies, coilin, cell nucleus, snRNP, pre-mRNA splicing, transcription
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