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The role of CUP-4 protein in Wnt signalling
Žídek, Radim ; Macůrková, Marie (advisor) ; Pospíchalová, Vendula (referee)
Wnt signalling is indispensible for proper development of organisms and maintaining of adult tissue homeostasis. Its disruption often leads to disease. In nematode Caenorhabditis elegans, Wnt signalling governs vast array of developmental processes, among others also migration of the Q neuroblasts and their descendants. The sole Wnt acting in this process, EGL-20, triggers the canonical β-catenin Wnt signal transduction pathway in QL but not in QR which leads to QL remaining in the posterior while the QR migrates anteriorly. This represents a useful tool for studying Wnt signalling. Recently, mutation of gene cup-4 was found to disrupt migration of the QL neuroblast in a small proportion of the mutant population. cup-4 encodes a ligand-gated ion channel family homologue and it was shown to participate in endocytosis by coelomocytes, specialized phagocytic cells in the C. elegans body cavity. Here, I present the results of my effort to determine the place of CUP-4 action in Wnt signalling and to elucidate the mechanism of its function. I found that CUP-4 acts upstream of PRY- 1/Axin, which is involved in signal transduction in signal receiving cells, and most probably downstream of adaptin AP2, which is important for recycling of Wnt cargo receptor Wntless (Wls) in Wnt producing cell. cup-4 also...
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Regulatory mechanisms of WNT signalling
Pospíchalová, Vendula ; Kořínek, Vladimír (advisor) ; Trka, Jan (referee) ; Bryja, Josef (referee)
AB T mu hom dise β sign mu liga stab tran sign T the focu disc cate of t cell targ the inte con sec I sign BSTRACT The Wnt si lticellular o meostasis. A eases, most β-catenin is nalling). In ltiprotein c ands when t bilized and nscription f nalling is tig This thesis knowledge uses on seq cusses the enin signall the Wnt pa ls of intest geted mous thesis des eraction wit nditional Hi retory cell t In conclusi nalling path T ignalling pa organisms Accordingly notably can s a central m n unstimula complex and they engage d transloca factors and ghtly regula is based on e of the reg quential po positive ro ling outcom athway whic tinal epithe e strains th scribes unp th members ic1 deletion types and en ion, our fin hway in dev athway is o ensuring s y, mutations ncer. mediator of ated cells d degraded e their recep tes to the to drive th ated at vario n four origin gulation of sttranslation ole of nucle me. The third ch reduces lium. Final at enable st ublished da s of the Wn n in the inte nhanced tum ndings contr velopment an one of the m successful s in the pat f canonical W β-catenin d in the pro ptors, degrad nucleus t he transcrip ous levels b nal articles f the Wnt s nal process ear protein d study repo the levels o lly, the las tudying the ata on the nt pathway, estinal epith mourigenesi ributed to t...
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Tumour Suppressor HIC1 - a novel inhibitor of Wnt Signalling
Pospíchalová, Vendula ; Kořínek, Vladimír (advisor) ; Filipp, Dominik (referee)
1. ABSTRACT In all metazoan organisms Wnt ligands regulate various developmental and physiological processes during embryogenesis and also in adult tissues. Moreover, deregulation in Wnt-related signalling is associated with several human disorders including cancer. In the so-called canonical pathway, activation of the Wnt receptor complex Frizzled/LRP triggers a complex network of molecular events that ultimately lead to the stabilization of β-catenin and formation of TCF/β- catenin heterodimers in the nucleus. These protein complexes drive expression of a specific set of genes that control the cell fate decision. The Wnt pathway is tightly regulated by several mostly negative feedback loops involving scores of extracellular, cytoplasmic or nuclear proteins. Recently, we have identified tumour suppressor Hypermethylated in cancer 1 (HIC1) as a negative modulator of canonical Wnt signalling. The HIC1 gene encodes a BTB/POZ-zinc finger transcriptional repressor. Interestingly, the HIC1-dependent repression of the TCF/β-catenin- dependent genes is not mediated by direct association of HIC1 with the regulatory regions of the Wnt-responsive genes but rather by a sequestration of TCF/β-catenin complexes to the nuclear speckle-like structures - the HIC bodies. These data indicate quite a pleiotropic role of HIC1...
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Regulatory mechanisms of WNT signalling
Pospíchalová, Vendula
AB T mu hom dise β sign mu liga stab tran sign T the focu disc cate of t cell targ the inte con sec I sign BSTRACT The Wnt si lticellular o meostasis. A eases, most β-catenin is nalling). In ltiprotein c ands when t bilized and nscription f nalling is tig This thesis knowledge uses on seq cusses the enin signall the Wnt pa ls of intest geted mous thesis des eraction wit nditional Hi retory cell t In conclusi nalling path T ignalling pa organisms Accordingly notably can s a central m n unstimula complex and they engage d transloca factors and ghtly regula is based on e of the reg quential po positive ro ling outcom athway whic tinal epithe e strains th scribes unp th members ic1 deletion types and en ion, our fin hway in dev athway is o ensuring s y, mutations ncer. mediator of ated cells d degraded e their recep tes to the to drive th ated at vario n four origin gulation of sttranslation ole of nucle me. The third ch reduces lium. Final at enable st ublished da s of the Wn n in the inte nhanced tum ndings contr velopment an one of the m successful s in the pat f canonical W β-catenin d in the pro ptors, degrad nucleus t he transcrip ous levels b nal articles f the Wnt s nal process ear protein d study repo the levels o lly, the las tudying the ata on the nt pathway, estinal epith mourigenesi ributed to t...
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The role of Disp3 gene in cell proliferation
Ditrychová, Karolína ; Zíková, Martina (advisor) ; Pospíchalová, Vendula (referee)
Dispatched 3 (DISP3), sterol - sensing domain (SSD) - containing protein, is a key focus of our laboratory. It was described as a gene regulated by thyroid hormone and its expression is mainly localized within neural tissue. Our preliminary data suggested increased DISP3 expression in medulloblastoma, a highly common pediatric cerebellar tumour, therefore we wanted to examine DISP3 role in human cancer cells. The aim of this thesis is to perform DISP3 overexpression and downregulation in human medulloblastoma cell lines and in mouse neural progenitors and analyse its effect on cell proliferation and differentiation. For this purpose, we chose DAOY and D341, human medulloblastoma cell lines with low and high expression of DISP3 and mouse multipotent neural progenitor cell line, C 17.2, with low DISP3 expression. We showed, that DISP3 ectopic expression leads to increase in cell proliferation in both DAOY and C 17.2 cells. Next, we examined the ability of C 17.2 cells to differentiate into neurons and astrocytes and observed, that cells overexpressing DISP3 reveal delay in differentiation, what we proved by analysis of cell specific markers. Using CRISPR-Cas9 targeting system, we reduced DISP3 expression within D341 cells and observed decrease in their proliferation. Finally, we analysed cell cycle...
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Regulatory mechanisms of WNT signalling
Pospíchalová, Vendula
AB T mu hom dise β sign mu liga stab tran sign T the focu disc cate of t cell targ the inte con sec I sign BSTRACT The Wnt si lticellular o meostasis. A eases, most β-catenin is nalling). In ltiprotein c ands when t bilized and nscription f nalling is tig This thesis knowledge uses on seq cusses the enin signall the Wnt pa ls of intest geted mous thesis des eraction wit nditional Hi retory cell t In conclusi nalling path T ignalling pa organisms Accordingly notably can s a central m n unstimula complex and they engage d transloca factors and ghtly regula is based on e of the reg quential po positive ro ling outcom athway whic tinal epithe e strains th scribes unp th members ic1 deletion types and en ion, our fin hway in dev athway is o ensuring s y, mutations ncer. mediator of ated cells d degraded e their recep tes to the to drive th ated at vario n four origin gulation of sttranslation ole of nucle me. The third ch reduces lium. Final at enable st ublished da s of the Wn n in the inte nhanced tum ndings contr velopment an one of the m successful s in the pat f canonical W β-catenin d in the pro ptors, degrad nucleus t he transcrip ous levels b nal articles f the Wnt s nal process ear protein d study repo the levels o lly, the las tudying the ata on the nt pathway, estinal epith mourigenesi ributed to t...
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Regulatory mechanisms of WNT signalling
Pospíchalová, Vendula ; Kořínek, Vladimír (advisor) ; Trka, Jan (referee) ; Bryja, Josef (referee)
AB T mu hom dise β sign mu liga stab tran sign T the focu disc cate of t cell targ the inte con sec I sign BSTRACT The Wnt si lticellular o meostasis. A eases, most β-catenin is nalling). In ltiprotein c ands when t bilized and nscription f nalling is tig This thesis knowledge uses on seq cusses the enin signall the Wnt pa ls of intest geted mous thesis des eraction wit nditional Hi retory cell t In conclusi nalling path T ignalling pa organisms Accordingly notably can s a central m n unstimula complex and they engage d transloca factors and ghtly regula is based on e of the reg quential po positive ro ling outcom athway whic tinal epithe e strains th scribes unp th members ic1 deletion types and en ion, our fin hway in dev athway is o ensuring s y, mutations ncer. mediator of ated cells d degraded e their recep tes to the to drive th ated at vario n four origin gulation of sttranslation ole of nucle me. The third ch reduces lium. Final at enable st ublished da s of the Wn n in the inte nhanced tum ndings contr velopment an one of the m successful s in the pat f canonical W β-catenin d in the pro ptors, degrad nucleus t he transcrip ous levels b nal articles f the Wnt s nal process ear protein d study repo the levels o lly, the las tudying the ata on the nt pathway, estinal epith mourigenesi ributed to t...
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The role of CUP-4 protein in Wnt signalling
Žídek, Radim ; Macůrková, Marie (advisor) ; Pospíchalová, Vendula (referee)
Wnt signalling is indispensible for proper development of organisms and maintaining of adult tissue homeostasis. Its disruption often leads to disease. In nematode Caenorhabditis elegans, Wnt signalling governs vast array of developmental processes, among others also migration of the Q neuroblasts and their descendants. The sole Wnt acting in this process, EGL-20, triggers the canonical β-catenin Wnt signal transduction pathway in QL but not in QR which leads to QL remaining in the posterior while the QR migrates anteriorly. This represents a useful tool for studying Wnt signalling. Recently, mutation of gene cup-4 was found to disrupt migration of the QL neuroblast in a small proportion of the mutant population. cup-4 encodes a ligand-gated ion channel family homologue and it was shown to participate in endocytosis by coelomocytes, specialized phagocytic cells in the C. elegans body cavity. Here, I present the results of my effort to determine the place of CUP-4 action in Wnt signalling and to elucidate the mechanism of its function. I found that CUP-4 acts upstream of PRY- 1/Axin, which is involved in signal transduction in signal receiving cells, and most probably downstream of adaptin AP2, which is important for recycling of Wnt cargo receptor Wntless (Wls) in Wnt producing cell. cup-4 also...
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Tumour Suppressor HIC1 - a novel inhibitor of Wnt Signalling
Pospíchalová, Vendula ; Filipp, Dominik (referee) ; Kořínek, Vladimír (advisor)
1. ABSTRACT In all metazoan organisms Wnt ligands regulate various developmental and physiological processes during embryogenesis and also in adult tissues. Moreover, deregulation in Wnt-related signalling is associated with several human disorders including cancer. In the so-called canonical pathway, activation of the Wnt receptor complex Frizzled/LRP triggers a complex network of molecular events that ultimately lead to the stabilization of β-catenin and formation of TCF/β- catenin heterodimers in the nucleus. These protein complexes drive expression of a specific set of genes that control the cell fate decision. The Wnt pathway is tightly regulated by several mostly negative feedback loops involving scores of extracellular, cytoplasmic or nuclear proteins. Recently, we have identified tumour suppressor Hypermethylated in cancer 1 (HIC1) as a negative modulator of canonical Wnt signalling. The HIC1 gene encodes a BTB/POZ-zinc finger transcriptional repressor. Interestingly, the HIC1-dependent repression of the TCF/β-catenin- dependent genes is not mediated by direct association of HIC1 with the regulatory regions of the Wnt-responsive genes but rather by a sequestration of TCF/β-catenin complexes to the nuclear speckle-like structures - the HIC bodies. These data indicate quite a pleiotropic role of HIC1...
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