|
|
Notch-independent functions of CSL transcription factors
Teska, Mikoláš ; Folk, Petr (advisor) ; Převorovský, Martin (referee) ; Kuthan, Martin (referee)
Notch pathway plays a critical role during development and life of Metazoan organisms. CBF1 is a component of the Notch pathway that mediates the regulation of target genes. The discovery of CBF1-like proteins in yeast raised the question of their function in unicellular organisms - before the origin of canonical Notch pathway. CBF1-homologs in yeast are conserved in parts that are important for DNA binding and bind to CBF1-binding elements in vitro. CBF1 and related transcription factors in Metazoa (CSL) interact with many proteins in Notch-dependent as well as Notch-independent complexes. The Notch receptor has likewise some CSL-independent functions. This assay reports about interacting partners of CSL in Metazoa along with homologous proteins in yeast with the aim to highlight potential interactions of CBF1-homologs in evolutionary ancestral context.
|
|
|
Hybrid sterility genes in mice: mapping of epistatic interactions
John, Václav ; Forejt, Jiří (advisor) ; Kuthan, Martin (referee)
MOUSE HYBRID STERILITY GENES: A MAPPING OF EPISTATIC INTERACTIONS Hybrid sterility is an important postmeiotic reproductive isolation barrier. The phenotype of mouse hybrid sterility includes decreased testes weight and an absence of sperm. It occurs only in F1 males from PWD/Ph (PWD; Mus musculus domesticus) x C57BL/6J (B6, M. m. musculus) cross but not reciprocal B6 x PWD F1 males (FOREJT & IVÁNYI, 1974; FOREJT et al., 1991). Nowadays we know that the phenotype of hybrid sterility is controlled by the PWD/B6 allelic combination on chromosome 17 at Prdm9 locus is needed and by the PWD allele on chromosome X at Hstx2 locus. This combination of two loci is necessary but not sufficient obtain full sterility (MIHOLA et al., 2008; FOREJT, JIŘÍ, pers. comm.), so another genes must play role. In this experimental work I prepared the F2 cross from B6 and PWD mouse strains and I genotyped the males of F2 crosses and I carried out the QTL analysis. Extended QTL analysis was carried out with all animals carrying Prdm9PWD/B6 - Hstx2PWD allelic combination. The results showed unexpectedly low number of sterile males in F2 generation (1.90 %), and significant QTLs on chromosomes 17 (in Prdm9 loci) and X (different from Hstx2) in sperm, no other significant peak on any chromosome was found. These results indicate a more...
|
|
|
Mammalian circadian clock in peripheral organs, molecular mechanism and entrainment
Polidarová, Lenka ; Kuthan, Martin (referee) ; Sumová, Alena (advisor)
Mammalian circadian clock in peripheral organs, molecular mechanism and entrainment The circadian system controls timing of behavioral and physiological processes in most organisms. In mammals, central oscillator is located in the suprachiasmatic nuclei (SCN) of the anterior hypothalamus. Apart from the SCN, peripheral oscillators are located in numerous organs like liver, heart, lung, muscle, intestine etc. The central and peripheral oscillators need to be synchronized by external cues (Zeitgeber). The SCN coordinates and entrains the phase of the clocks in numerous peripheral tissues via neuronal and humoral signals. For the SCN, dominant synchronizer is external light-dark cycle. Peripheral oscillators are cell-autonomous, they could work also independently of the SCN as a consequence of a feeding cycle. The basic molecular core clock mechanism responsible for generating circadian rhythms in the central and peripheral clocks is composed of transcriptional/translational feedback loops between the clock genes and their protein products. The aim of the present thesis was to ascertain whether the clock gene and protein expressions exhibit circadian rhythms in the rat intestine and whether the core clock mechanism drives expression of a cell cycle regulator rWee1. Next aim was to reveal how the circadian...
|
|
| |
|
|
A comparison of SH3 domains' tyrosine phosporylation influence on their binding capacity
Tatárová, Zuzana ; Novotný, Marian (advisor) ; Kuthan, Martin (referee)
Understanding the impact of protein phosphorylation is very important for the formation of dynamic biological processes such as gene silencing, cell growth, differentiation or apoptosis. This work deals with the phosphorylation of a protein-interaction module known as SH3 domain and the influence of phosphorylation on its ligand-binding capacity. SH3 domain is a part of a large number of enzymes directly involved in signal transduction as well as adapter proteins without enzymatic activity. Many studies have shown the importance of tyrosine sites within SH3 domain in regulatory mechanisms of proteins by using either mutants that cannot be phosphorylated, mutants mimicking the negative charges created by phosphorylation or by evidence of in vivo phosphorylation. The work also includes bioinformatic analysis, which further expand our knowledge of SH3 phosphorylated proteins and confirms that phosphorylation of the tyrosine sites is conserved among proteins containing the SH3 domain.
|
|
|
Signalization of adenylate cyclase toxin of Bordetella pertussis in macrophages.
Černý, Ondřej ; Kuthan, Martin (referee) ; Kamanová, Jana (advisor)
Adenylate cyclase toxin (CyaA) is a key virulence factor of Bordetella pertussis, the causative agent of whooping cough. The toxin targets primarily myeloid phagocytes expressing CD11b/CD18 (αMβ2, CR3, Mac-1) and by elevation of cytosolic cAMP levels it paralyses their macropinocytic and opsono-phagocytic functions. Here, we dissected the cAMP-regulated pathway responsible for the block of macrophage macropinocytosis and characterized the capacity of CyaA-treated macrophages to shut- down Akt (protein kinase B, PKB) signaling; that controls nitric oxide (NO) production by macrophages. By using specific activators of protein kinase A (PKA) and for the exchange protein activated by cAMP (Epac), we show that activation of the cAMP effector Epac inhibits macropinocytosis in macrophages. Moreover, upon transfection of macrophages by the constitutively active and dominant negative variants of a downstream effector of Epac, the small GTPase Rap1, inhibition or upregulation of macrophage macropinocytosis was observed, respectively. It was reported previously that the Epac/Rap1 pathway regulates activity of tyrosin phosphatase SHP-1 as well as of protein phosphatase 2 A (PP2A). We show that inhibition of both tyrosin phosphatases and PP2A interferes with CyaA-mediated block of macropinocytosis. These...
|
|
|
Signalization in the ontogeny of bacterial colonies
Čepl, Jaroslav ; Markoš, Anton (advisor) ; Kuthan, Martin (referee)
Bacterial bodies (colonies) can develop complex patterns of color and structure. These patterns may arise as a result of both colony-autonomous processes (self-patterning) and environmental influences, including those generated by neighbor bodies. We have studied the interplay of intra-colony signaling (self-patterning) and inter-colony influences in related clones of Serratia rubidaea on rich media. We show that the mutual influencing of colonies, present in a common morphospace, is communicated by at least two putative signals. A model accounting for some aspects of colony morphogenesis and inter-colony interactions is proposed. Key words bacteria; Serratia sp.; airborne signals; colony morphogenesis
|
|
| |
|
| |
|
| |
guest ::
