Molecular analysis of a t(11;22) translocation junction in a case of Ewing's sarcoma.
Polymerase chain reaction (PCR)-directed sequence analysis was performed to characterize the genomic and cDNA breakpoint junctions of t(11;22) (q24;q12) translocation in a case of Ewing's sarcoma, in which the EWS gene located on chromosome 22 is rearranged with the FL11 gene located on chromosome 11. RNA-PCR revealed the novel chimeric product of EWS/FL11 gene on the derivative chromosome (der) 22, resulting from a probable fusion of EWS exon 7 to FL11 exon 9. Sequencing of the PCR-amplified genomic fragments of the fusion genes showed that the breakpoints on der(22) occurred in EWS intron 7 and, most probably, in FL11 intron 8. Those of the untranscribed counterpart on der(11) were located in the same FL11 intron and in EWS exon 11, with deletion of a considerable amount of sequences from both genes. These findings indicate asymmetric junction at the molecular level in the present t(11;22). None of the reported conserved sequences that mediate other cancer chromosome translocations was observed around the genomic junctions. Instead, a palindromic hexamer 5'-GCTAGC-3' was found to flank the breakpoints of both genes on der(22), which may have a functional significance in the genesis of the t(11;22).
Bhagirath
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Chromosome Research Unit, Faculty of Science, Hokkaido University, Sapporo, Japan.
Abe
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Nojima
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Yoshida
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MC
D000293:Adolescent; D000595:Amino Acid Sequence; D001483:Base Sequence; D002880:Chromosomes, Human, Pair 11; D002892:Chromosomes, Human, Pair 22; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D012091:Repetitive Sequences, Nucleic Acid; D012512:Sarcoma, Ewing / Q000235:genetics*; D014178:Translocation, Genetic