Project description:The KMT2A/MLL1 lysine methyltransferase complex is an epigenetic regulator of selected developmental genes, in part through the SET-domain-catalyzed methylation of H3K4. It is essential for normal embryonic development and haematopoiesis and frequently mutated in cancer. The catalytic properties and targeting of KMT2A/MLL1 depend on the proteins with which it complexes and the post-translational protein modifications which some of these proteins put in place, though detailed mechanisms remain unclear. We have shown that KMT2A/MLL1 (both native and FLAG-tagged) and Msk1 (RPS6KA5), co-immunoprecipitated in various cell types. This experiment showed that the great majority of genes whose activity changed on KTM2A/MLL1 knockdown responded comparably to Msk1 knockdown.
Project description:KMT2A (alias MLL) is located at chromosomal position 11q23 and en-codes histone methyltransferase 2A which activates genes via methylation of histone H3 lysine K4 in their chromatin. Mutations of KMT2A, including partial tandem duplication (PTD) and fusion with partner genes are present in both lymphoid and myeloid acute leukemia. More than 100 different KMT2A fusion genes are described while only some of them are represented in cell line models. Cytogenetic and genomic copy number analyses, PCR, Western blot and RNA-sequencing were performed to characterize aberrations in acute myeloid leukemia (AML) cell line KOPM-88. Bioinformatic analysis of public AML patient data revealed differentially expressed genes. Functional analyses were performed in KOPM-88 by siRNA-mediated knockdown and life-cell imaging. AML cell line KOPM-88 is derived from a boy at relaps and has been reported to contain t(X;11)(q24;q23) with uncharacterized breakpoints. We identified in KOPM-88 fusion gene KMT2A::SEPTIN6 generated by this rearrangement and excluded KMT2A-PTD. KMT2A::SEPTIN6 activated BMP-signalling and inhibited expression of HOXA7 and HOXA9. BMP-signalling in turn activated cell proliferation by CDNK2B inhibition. KOPM-88 contains fusion gene KMT2A::SEPTIN6, representing the only cell line model for this type of KMT2A-rearrangement. KOPM-88 may serve to test novel therapeutic treatments for KMT2A::SEPTIN6-positive AML.
