Supraphysiologic levels of the AML1-ETO isoform AE9a are essential for transformation

Kevin A. Link, Shan Lin, Mahesh Shrestha, Melissa Bowman, Mark Wunderlich, Clara D. Bloomfield, Gang Huang, James C. Mulloy

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


Chromosomal translocation 8;21 is found in 40% of the FAB M2 subtype of acute myeloid leukemia (AML). The resultant in-frame fusion protein AML1-ETO (AE) acts as an initiating oncogene for leukemia development. AE immortalizes human CD34+ cord blood cells in longterm culture. We assessed the transforming properties of the alternatively spliced AE isoform AE9a (or alternative splicing at exon 9), which is fully transforming in a murine retroviral model, in human cord blood cells. Full activity was realized only upon increased fusion protein expression. This effect was recapitulated in the AE9a murine AML model. Cotransduction of AE and AE9a resulted in a strong selective pressure for AE-expressing cells. In the context of AE, AE9a did not show selection for increased expression, affirming observations of human t(8;21) patient samples where full-length AE is the dominant protein detected. Mechanistically, AE9a showed defective transcriptional regulation of AE target genes that was partially corrected at high expression. Together, these results bring an additional perspective to our understanding of AE function and highlight the contribution of oncogene expression level in t(8;21) experimental models.

Original languageEnglish (US)
Pages (from-to)9075-9080
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number32
StatePublished - Aug 9 2016
Externally publishedYes


  • AML
  • Isoform
  • Oncogene dosage
  • Transformation

ASJC Scopus subject areas

  • General


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