Chromosome aberrations associated with CAD gene amplification in Chinese hamster cultured cells |
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Authors: | L Ottaggio C Agnese S Bonatti P Cavolina A De Ambrosis P Degan A Di Leonardo M Miele R Randazzo A Abbondandolo |
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Institution: | Laboratory of Mutagenesis, IST, Genoa, Italy. |
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Abstract: | Eleven sublines with increasing resistance to N-phosphonacetyl-L-aspartate (PALA) were isolated from the V79,B7 Chinese hamster cell line. Aspartate transcarbamylase activity and CAD gene copy number increased with increasing resistance of sublines. In situ hybridization with a DNA probe for the CAD gene showed that the amplified sequences resided in the terminal region of a marker chromosome with elongated q arms. This region stained homogeneously after G-banding. A high incidence of both numerical and structural chromosome aberrations was found in PALA-resistant cells. In hyperdiploid and polyploid cells, containing 2 copies of the marker chromosome, dicentrics were found at a very high frequency. As indicated by in situ hybridization and G-banding, they originated from a rearrangement involving 2 homologous marker chromosomes. |
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