Using sequential RNA-DNA fluorescence in situ hybridization, the nuclear arrangement of both the active and inactive c-myc gene as well as its transcription was investigated in colon cancer HT-29 cells induced to differentiate into enterocytes. Cytogenetic studies revealed the presence of two chromosomes 8 in HT-29 cells, of which the one containing c-myc gene amplicons was substantially larger and easily distinguished from the normal chromosome. This observation enabled detection of both activity and nuclear localization of c-myc genes in single cells and in individual chromosome territories. Similar transcriptional activity of the c-myc gene was observed in both the normal and derivative chromosome 8 territories showing no influence of the amplification on the c-myc gene expression. Our experiments demonstrate strikingly specific nuclear and territorial arrangements of active genes as compared with inactive ones: on the periphery of their territories facing to the very central region of the cell nucleus. Nuclear arrangement of c-myc genes and transcripts was conserved during cell differentiation and, therefore, independent of the level of differentiation-specific c-myc gene expression. However, after the induction of differentiation, a more internal territorial location was found for the single copy c-myc gene of normal chromosome 8, while amplicons conserved their territorial topography.

• MeSH
• adenokarcinom metabolismus   MeSH
• azidy MeSH
• buněčná diferenciace MeSH
• buněčné jádro MeSH
• enterocyty fyziologie   MeSH
• genetická transkripce MeSH
• genová dávka MeSH
• geny APC MeSH
• geny myc * MeSH
• lidé MeSH
• lidské chromozomy, pár 8 metabolismus   MeSH
• nádorové biomarkery analýza   MeSH
• nádorové buněčné linie MeSH
• nádory tračníku metabolismus   MeSH
• proliferace buněk MeSH
• protoonkogenní proteiny c-myc metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• azidy MeSH
• hydroxysuccinimidyl-4-azidobenzoate MeSH Prohlížeč
• nádorové biomarkery MeSH
• protoonkogenní proteiny c-myc MeSH

In two tumour sublines (T.wt/BL and T.wt/Bc), established from mammary adenocarcinomas caused by mouse polyoma (Py) infection of nu/nu mice, integration of polyomavirus DNA sequences into the c-myc gene locus was mapped. A complete Py genome was found to be integrated just upstream from the c-myc gene in T.wt/BL cell line, while only a part of the early Py region coding for the early proteins was inserted in the chromosomal DNA of T.wt/Bc cells. An interference of Py sequences with the regulation of c-myc gene expression gives further significance to a Py-derived tumour system that appears to be similar to some human mammary cancers in the modifications of c-myc expression. Both cell lines were found to produce truncated large T antigen and entire middle and small T antigens. In addition, production of VP1 protein was observed in the T.wt/BL cell line. The integration of polyomavirus sequences and/or expression of viral proteins caused an elevation of c-myc expression. The level of the c-myc expression was higher in both tumour cell lines in comparison with control normal murine mammary gland (NMuMG) lines, but substantially lower than in NMuMG cells infected with polyomavirus. Possible co-operation of Py proteins with c-Myc was examined. Through GST fusion protein pull-down experiments, we evidenced, that c-Myc forms a complex with the common part of the Py early antigens in the two tumour cell lines. Co-localisation of the c-myc and LT was observed in cells overexpressing c-Myc and LT.

• MeSH
• adenokarcinom genetika   virologie   MeSH
• antigeny transformující polyomavirové genetika   metabolismus   MeSH
• DNA nádorová analýza   MeSH
• DNA virů analýza   MeSH
• experimentální nádory mléčných žláz genetika   virologie   MeSH
• geny myc fyziologie   MeSH
• glutathiontransferasa metabolismus   MeSH
• integrace viru * MeSH
• lidé MeSH
• mléčné žlázy lidské fyziologie   virologie   MeSH
• myši MeSH
• Polyomavirus genetika   MeSH
• protoonkogenní proteiny c-myc genetika   metabolismus   MeSH
• virová transformace buněk MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• antigeny transformující polyomavirové MeSH
• DNA nádorová MeSH
• DNA virů MeSH
• glutathiontransferasa MeSH
• protoonkogenní proteiny c-myc MeSH