Chromosome 5 complement of the HeLa parental cell line used for the construction of defective cell lines. In all instances, the DHFR probe is labeled in green, whereas whole chromosome 5 painting and the BAC clone RP11-297G19 are labeled in red. FISH using the human chromosome 5 painting revealed the presence of seven chromosomes (A, B, C, D, E, F and G) with complete or partial homology to human chromosome 5. Chromosome A corresponds to a normal human chromosome 5 with a deletion of the chromosomal band 5q35; this organization was demonstrated by the lack of hybridization signal using the BAC clone RP11-117L6 (data not shown). Chromosome C corresponds to a translocated derivative chromosome between 5q and the short arm of chromosome 3 [der(3p5q)]. Chromosome B contains the region corresponding to 5q22.2-q35 translocated with an unknown chromosome, whereas chromosome D corresponds to 5q14-qter also translocated with another chromosome. In addition, chromosome F is an isochromosome of the p arm [i(5p)].