Detection of CBFbeta/MYH11 fusion transcripts and study of the mechanism of leukemogenesis of CBFbeta/SMHHC fusion protein / 中华血液学杂志

ABSTRACT

<p><b>OBJECTIVE</b>To explore CBFbeta/MYH11 fusion transcripts and its expressing product CBFbeta/SMHHC fusion protein in mechanism of leukemogenesis.</p><p><b>METHODS</b>CBFbeta/MYH11 fusion transcripts were detected by combined RT-PCR with sequencing. Transcription assays were examined using pM-CSFR-Luc as reporting plasmid, and subcellular localization of encoding proteins were assayed by double immunofluorescent staining and Western blot.</p><p><b>RESULTS</b>Two types of CBFbeta/MYH11 fusion transcripts were found in 26 patients with acute leukemia, most being of type A (23/26 cases, 92%) and a few of type D (2/26 cases, 8%). The inhibition of CBF-mediated M-CSFR promotor transactivation by CBFbeta/SMHHC fusion protein was increasing with the increase in amount of the fusion protein. CBFalpha subunit (AML1) located in nucleus, both CBFbeta subunit (CBFbeta) and CBFbeta/SMHHC located in cytoplasm. When AML1 and CBFbeta were coexpressed, CBFbeta still located mainly in cytoplasm, but when AML1 and CBFbeta/SMHHC were coexpressed, CBFbeta/SMHHC located mainly in nucleus.</p><p><b>CONCLUSIONS</b>(1) The types of CBFbeta/MYH11 fusion transcripts of Chinese leukemia patients are almost the same as that reported in western literature. (2) CBFbeta/SMHHC inhibits CBF-mediated transactivation through competing with CBFbeta for binding to AML1.</p>