AML-2 is a potential target for transcriptional regulation by the t(8;21) and t(12;21) fusion proteins in acute leukemia.

Meyers S, Lenny N, Sun W, Hiebert SW
Oncogene. 1996 13 (2): 303-12

PMID: 8710369

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.

MeSH Terms (29)

Acute Disease Amino Acid Sequence Animals Antibody Specificity Base Sequence Chromosomes, Human, Pair 8 Chromosomes, Human, Pair 12 Chromosomes, Human, Pair 21 Core Binding Factor Alpha 2 Subunit DNA DNA-Binding Proteins Humans Leukemia Mice Mice, Inbred C57BL Molecular Sequence Data Neoplasm Proteins Proto-Oncogene Proteins Proto-Oncogene Proteins c-ets Rats Rats, Inbred BUF Recombinant Fusion Proteins Repressor Proteins RUNX1 Translocation Partner 1 Protein Transcription, Genetic Transcriptional Activation Transcription Factors Translocation, Genetic Tumor Cells, Cultured

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