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Rozdílná jaderná lokalizace aberantních a normálních homologů chromosomu 8 v intaktních nebo NaBt diferencovaných buňkách HT-29
Harničarová, Andrea ; Bártová, Eva ; Kozubek, Stanislav
An accumulation of numerous chromosomal structural aberrations is a typical feature of the human colon adenocarcinoma cell line HT-29. In these cells the chromosome 8 territories were visualized using fluorescence in situ hybridisation (FISH), which enabled to distinguish the aberrant chromosome 8 homologue from the normal one. Analyses of nuclear parameters revealed differences in radial positioning between chromosome homologues analysed. In comparison with an normal chromosome 8, the aberrant chromosome 8 territory was positioned closer to the nuclear periphery. Under standard conditions HT-29 cells displayed relatively undifferentiated phenotype but incubation of these cells in the presence of sodium butyrate (5mM) induced biochemical and morphological changes that are typical of well-differentiated phenotype of enterocytes.
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Cytologická studie modelů DNA metylace a metylace histonů u lidských buněčných linií
Skalníková, M. ; Bártová, Eva ; Kozubek, Stanislav ; Kozubek, Michal
Epigenetic processes are defined as heritable changes in genome function that occur without a change in DNA sequence. Gene expression, chromosome segregation, DNA replication, repair, and recombination all act, not on DNA alone, but on the chromatin template. DNA methylation, along with histone lysine methylation, establishes the framework for long-term epigenetic maintenance. The discovery that enzymes can (re)organise chromatin into accessible and inaccessible configurations revealed epigenetic mechanisms that considerably extend the information potential of the genetic code. In mammals, heterochromatin is characterised by DNA methylation at CpG dinucleotides and methylation at lysine 9 of histone 3 (H3-K9), whereas euchromatin is associated with methylation at lysine 4 of histone 3 (H3-K4).
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Analýza genové exprese kolorektálního karcinomu detekované cDNA mikročipy pomocí kombinace různých vyhodnocovacích přístupů
Jansová, E. ; Krontorád, P. ; Svoboda, Z. ; Koutná, I. ; Pavlík, T. ; Kozubek, Michal ; Jarošová, M. ; Žaloudík, J. ; Kozubek, Stanislav
We have compared colorectal carcinoma tissues with parallel samples of epithelial tissue and identified, by means of Human 1.7K cDNA microarrays, a set of genes with significantly altered expression in 12 patients. We used a combination of several approaches of microarray data analysis to be sure that the results were reliable. Although we have found differences between the results obtained by various image analysis software packages and using different statistical tools, we have identified the group of 22 genes with significantly altered expression in colorectal carcinoma tissue as compared with epithelial tissue using all evaluation approaches. Hierarchical clustering showed the possibility of dividing the patients into two groups according to the presence of metastases in regional lymph nodes. We have proposed 6 genes as potential markers for the detection of the presence of regional metastases in patients.
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Methylace histonu H3K9 v lidských krevních buňkách a v granulocytech pacientů s myeloidní leukemií
Lukášová, Emilie ; Falk, Martin ; Kořistek, Z. ; Kozubek, Stanislav ; Grigoryev, S. ; Kozubek, Michal ; Ondřej, Vladan ; Kroupová, I.
Common heterochromatin antigenic protein markers while present in human blood progenitor CD34+ cells, differentiated lymphocytes and monocytes are absent in neutrophile granulocytes and, to large extent, in eosinophiles. In acute CML and AML, strong methylation of H3K9 and all isoformes of HP1 are detected. In chronic forms of CML, no strong correlations among the level of histone methylation, disease progression and modality of treatment were observed. Reprogramming of leukemia HL60 cells to terminal differentiation by retinoic acid does not eliminate histone H3K9 methylation and the presence of HP1 isoformes from differentiated granulocytes. Our study shows for the firs time that histone H3 methylation may be dramatically changed during normal cell differentiation.
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