AML-2 is a potential target for transcriptional regulation by the t(8;21) and t(12;21) fusion proteins in acute leukemia.
AML-1B is targeted directly and indirectly in multiple chromosomal translocations in myeloid and B-cells. The AML-1/ETO and TEL/AML-1 fusion proteins, created by the t(8;21) and t(12;21) respectively, disrupt AML-1B-dependent transcription. Recently, two human members of the runt homology domain family of transcription factors have been identified, AML-2 and AML-3, which also regulate transcription through enhancer core motifs. If multiple factors regulate transcription through the same site, a dominant interfering protein may be required to promote leukemogenesis, rather than the inactivation of both AML1 alleles. To determine which AML family proteins are active in hematopoietic cells, we developed antisera specific to each family member for use in gel mobility shift assays. We have found that AML-1B is the major DNA binding activity in T-cell lines, while both AML-1B and AML-2 are expressed in myeloid and B-cell lines. AML-1B represents most of the active protein in the mouse thymus, whereas AML-1 and AML-2 are equally expressed in the mouse spleen. AML-3 is expressed at very low levels in a single myeloid cell line, 32D.3, and is the only core binding activity present in Buffalo rat liver cells. We demonstrate that AML-2-dependent transactivation mediated by enhancer core motifs is inhibited by the AML-1/ETO and TEL/AML-1 fusion proteins. This indicates that the t(8;21) and t(12;21) fusion proteins inhibit transcriptional activation by the AML-1 transcription factor family, and in so doing contributes to leukemogenesis.
Meyers
S
S
Department of Tumor Cell Biology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA.
Lenny
N
N
Sun
W
W
Hiebert
S W
SW
D000208:Acute Disease; D000595:Amino Acid Sequence; D000818:Animals; D000918:Antibody Specificity; D001483:Base Sequence; D002881:Chromosomes, Human, Pair 12; D002891:Chromosomes, Human, Pair 21; D002898:Chromosomes, Human, Pair 8; D050676:Core Binding Factor Alpha 2 Subunit; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D006801:Humans; D007938:Leukemia / Q000235:genetics* / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D011518:Proto-Oncogene Proteins; D050783:Proto-Oncogene Proteins c-ets; D000075142:RUNX1 Translocation Partner 1 Protein; D051381:Rats; D011915:Rats, Inbred BUF; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D012097:Repressor Proteins; D014157:Transcription Factors / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D014178:Translocation, Genetic; D014407:Tumor Cells, Cultured; D000097764:ETS Translocation Variant 6 Protein
D050676:Core Binding Factor Alpha 2 Subunit; D004247:DNA; D004268:DNA-Binding Proteins; D009363:Neoplasm Proteins; D011518:Proto-Oncogene Proteins; D050783:Proto-Oncogene Proteins c-ets; D000075142:RUNX1 Translocation Partner 1 Protein; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; D014157:Transcription Factors; D000097764:ETS Translocation Variant 6 Protein; C493728:RUNX1 protein, human; C082222:RUNX1T1 protein, human; C493726:Runx1 protein, mouse; C493727:Runx1 protein, rat