Master Degree / Yüksek Lisans Tezleri

Permanent URI for this collectionhttps://hdl.handle.net/11147/3008

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  • Master Thesis
    Investigation of the Effects of Gtf2a1-Antisense Long Non-Coding Rna on Cell Fate
    (01. Izmir Institute of Technology, 2022) Çiftçi, Yusuf Cem; Akgül, Bünyamin
    Apoptosis is a distinct mode of programmed cell death whereby cellular contents are broken down and accumulated in the apoptotic bodies. The vast majority of the genome consists of non-coding RNAs (ncRNA). NcRNAs can be divided into groups depending on their length, for example, long non-coding RNA (lncRNA) longer than 200 nucleotides. It has been demonstrated that these have important roles in the development, and treatment of cancer and in other diseases that critically affect human life. Considering the lncRNAs’ mechanisms of action on apoptosis, they modulate activity of transcription factors, regulate miRNAs, and interact with proteins related to histone mechanisms such as chromatin modifier. In this perspective, GTF2A1-AS which is an uncharacterized and novel lncRNA was found as one of highly expressed lncRNA in transcriptomic data obtained from HeLa cells treated with cisplatin. The potential role of GTF2A1-AS within the cell was investigated through the transcriptomic data provided by GTF2A1-AS knockdown. It has been found that specific gene clusters mainly enriched in the pathway which is Defective Homology directed Repair through Homologous Recombination. In this process, double-strand breaks are repaired with the help of BRCA1/2, RAD50, RAD51, PALB2 proteins which are known as DNA damage response proteins. Thus, the genes related with DNA damage response were selected to validate the transcriptomic data. In light of this information, GTF2A1-AS knockdown has resulted in an increase in the early apoptosis in HeLa cells. Additionally, when GTF2A1-AS knockdown was combined with cisplatin, it sensitized HeLa cells against cisplatin by affecting late apoptosis, specifically. Consequently, GTF2A1-AS as a cisplatin inducible lncRNA modulates apoptosis and chemosensitivity in HeLa cells.
  • Master Thesis
    Investigation of the Interaction Between Dr5-As Long Noncoding Rna and Caprin1 Protein
    (Izmir Institute of Technology, 2022) Kaçar, Vahide İlayda; Akgül, Bünyamin
    Cell proliferation is the crucial process for many physiological incidents such as tissue and organ development, wound healing, and immune system reactions. It is achieved by the growth and division of cells in a multicellular organism. Investigation of molecules involved in the regulation of cell cycle mechanism provides insight into reasons and treatments of the diseases such as cancer. In recent years, information that acquired from deep sequencing reveals that several proteins and non-coding RNAs have crucial role in the regulation of cell cycle and proliferation. Death receptor 5 antisense (DR5-AS) is a novel long non-coding RNA (lncRNA) transcript that is cisplatin inducible and is involved in modulation of cell proliferation and cell cycle in HeLa cells. When DR5-AS lncRNA was knocked down, the morphology of HeLa cells became spherical without inducing apoptosis. Although this lncRNA reduces cell proliferation via a cell cycle arrest at S and G2/M phases, mechanism behind this cell cycle arrest is not known. lncRNAs work in complexes with RNA, DNA, and protein interactions in the cell. There are several experimental and bioinformatical approaches to investigate RNA: protein interactions such as PAR-CLIP. In this approach, proximal protein and RNAs are covalently bonded with UV radiation. Then this complex is immunoprecipitated with specific antibodies. According to PAR-CLIP data of DR5-AS lncRNA, CAPRIN1 is a cell cycle associated protein that has the highest interaction score. The results suggest that CAPRIN1 and DR5-AS work reversely in cell proliferation although under the cisplatin treatment, CAPRIN1 enhances the expression of DR5-AS lncRNA. All these observations were confirmed by many quantitative experiments. Conclusively, this study provides a clue about how DR5-AS lncRNA might regulate cell cycle and proliferation through CAPRIN1 protein.
  • Master Thesis
    Investigation of the Effect of Dr5-As Long Non-Coding Rna on Cell Proliferation
    (Izmir Institute of Technology, 2020) Gürer, Dilek Cansu; Akgül, Bünyamin
    Cell proliferation is the process of increasing cell number in a multicellular organism. In literature, there are numerous proteins and non-coding RNAs reported as regulators of cell proliferation, yet, many of others are waiting to be explored. Unravelling the mechanism behind the regulation of cell proliferation is crucial to develop new strategies for fighting numerous diseases such as cancer, immune diseases, or neurodegenerative diseases. Long non-coding RNAs (lncRNAs) are known to regulate various cellular processes. To determine which ones are related to cell proliferation and apoptosis in HeLa cells, a transcriptomics study was performed under cisplatin, doxorubicin, TNF-? and Anti-Fas treatments. DR5-AS is a novel lncRNA transcript selected from this transcriptomics study as a promising regulatory lncRNA candidate due to its overlap with DR5 protein-coding gene which is known to regulate apoptosis and proliferation. Several phenotypic characterization methods were performed to understand the function of DR5-AS lncRNA. These studies showed that DR5-AS knockdown causes a significant decrease in cell proliferation, an alteration in the normal HeLa cell morphology, a shift through S and G2/M phases in cell cycle profile, and significant accumulation of cells in the metaphase phase. A second transcriptomics study was performed with DR5-AS knockdown HeLa cells to uncover which pathways are responsible for these changes. The results suggest that DR5-AS lncRNA regulates expression of numerous key proteins in cell cycle regulation. This observation was confirmed by several qPCR experiments. In conclusion, this study provides the first evidence that DR5-AS lncRNA modulates cell cycle and proliferation in HeLa cells.
  • Master Thesis
    Molecular Characterization of the Gtf2a-1 Antisense Long Non-Coding Rna
    (Izmir Institute of Technology, 2017) Yarımçam, Murat Caner; Akgül, Bünyamin
    One of the essential events in cell regulation and normal development of an organism is apoptosis. The dysregulation of apoptosis is associated with diseases such as cancer. Apoptosis induction can kill cancer cells without harming the individual. For this purpose, new methods are developed to fight the cancer cells. One of the novel approaches is based on long non-coding RNAs (lncRNAs). LncRNAs are differentially expressed in cancer cells and they regulate and interact essential pathways. The ones related to apoptosis are the targets. In this study, target lncRNA was determined based on RNA-Seq data. Then apoptosis was induced in HeLa cells with cisplatin and qRT-PCR was performed with isolated RNAs from the cells to validate the data with regard to upregulation of GTF2A-1 anti-sense lncRNA in apoptosis. Then GapmeR specific to target lncRNA was designed and transfected into HeLa cells in order to induce apoptosis. After induction of apoptosis, total RNA and protein were isolated from the cells. qRTPCR was performed to validate the RNA-Seq data. Western blotting was performed in order to characterize the target lncRNA by controlling its effects on different apoptosis pathways. Western blotting results are showing resemblance between GTF2A-1 antisense lncRNA silencing-induced apoptosis and cisplatin-induced apoptosis. The western blotting result of Cytochrome c is interesting because its amount is decreased in GTF2A- 1 anti-sense lncRNA silencing-induced apoptosis. The candidate, GTF2A-1 anti-sense lncRNA, is directly regulating the apoptosis in HeLa cells and in this study, some of the pathways that are regulated with this lncRNA were shown.