Identification of CBL, a proto-oncogene at 11q23.3, as a novel MLL fusion partner in a patient with de novo acute myeloid leukemia.
We have shown that the CBL gene at 11q23.3, telomeric to MLL, was fused to MLL in an adult patient with de novo acute myeloid leukemia (FAB-M1). Southern blot analysis indicated that the MLL rearrangement was involved in the chromosomal abnormality. cDNA panhandle polymerase chain reaction identified the fusion transcript, in which MLL exon 6 was fused in-frame with CBL exon 8. Long-distance PCR amplified the genomic junction region, which involved the fusion of the 3' portion of an Alu element in intron 6 of MLL with the 5' portion of an Alu element in intron 7 of CBL. The absence of extensive sequence similarity at both breakpoints of MLL and CBL indicated that the recombination was not generated through homologous recombination. MLL and CBL are located between STS markers D11S939 and D11S924. Analysis of the sequence demonstrated that the transcriptional orientation of both genes at 11q23.3 is from centromere to telomere. The results of Southern blotting in conjunction with fluorescence in situ hybridization suggest that the MLL-CBL fusion was the result of an interstitial deletion. CBL, a proto-oncogene, functions as a negative regulator of several receptor protein-tyrosine-kinase signaling pathways and as an adaptor protein in tyrosine phosphorylation-dependent signaling. CBL is the second gene at 11q23.3 found to fuse with MLL.
Fu
Jen-Fen
JF
Department of Medical Research, Chang Gung Memorial Hospital, Taoyuan, Taiwan.
Hsu
Jia-Jong
JJ
Tang
Tzung-Chih
TC
Shih
Lee-Yung
LY
D000328:Adult; D000595:Amino Acid Sequence / Q000235:genetics; D001483:Base Sequence / Q000235:genetics; D019457:Chromosome Breakage / Q000235:genetics; D002880:Chromosomes, Human, Pair 11 / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000235:genetics*; D005260:Female; D011495:Histone-Lysine N-Methyltransferase; D006801:Humans; D015470:Leukemia, Myeloid, Acute / Q000175:diagnosis / Q000235:genetics*; D008969:Molecular Sequence Data; D051788:Myeloid-Lymphoid Leukemia Protein; D015514:Oncogene Proteins, Fusion / Q000235:genetics*; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D050721:Proto-Oncogene Proteins c-cbl; D011519:Proto-Oncogenes; D014157:Transcription Factors; D044767:Ubiquitin-Protein Ligases
D004268:DNA-Binding Proteins; C497422:KMT2A protein, human; C000715470:MAS1 protein, human; D015514:Oncogene Proteins, Fusion; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins; D014157:Transcription Factors; D051788:Myeloid-Lymphoid Leukemia Protein; D011495:Histone-Lysine N-Methyltransferase; D050721:Proto-Oncogene Proteins c-cbl; D044767:Ubiquitin-Protein Ligases; C067419:CBL protein, human