BMI1 reprogrammes histone acetylation and enhances c-fos pathway via directly binding to Zmym3 in malignant myeloid progression.
Bottom Line: By using chromatin immunoprecipitation (ChIP) collaborated with secondary generation sequencing and verified by ChIP-PCR, we found that BMI1 directly bound to the promoter region of Zmym3, which encodes a component of histone deacetylase-containing complexes.In addition, as one of the downstream target genes of this complex, c-fos was activated with increasing histone acetylation when ZMYM3 was suppressed in the Bmi1-transfected cells.These results suggested that BMI1 may reprogramme the histone acetylation profile in multiple genes through either indirect or direct binding effects which probably contributes to the malignant progression of myeloid progenitor cells.
Affiliation: Key Laboratory of Thrombosis and Hemostasis of Ministry of Health, Jiangsu Institute of Hematology, The First Affiliated Hospital of Soochow University, Soochow, China.Show MeSH
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Mentions: To seek the possible direct target gene of BMI1, we have performed ChIP sequencing on the K562 and SKM-1 cells. A list of several dozens of genes with various functions could be obtained and judged to be directly bound by BMI1. Among them, Zmym3, which translates a component of histone deacetylase-containing multiprotein complexes, was confirmed to be the direct target of BMI1. Furthermore, ChIP-PCR assay using antibody against ubiquitin-H2A, a substrate of PRC1, also indicated that Zmym3 gene promoter region could be amplified from the precipitations in K562, U937 and SKM-1. In comparison with the parental K562 cells and K562 cells transfected with MSCV vector, the amplified product of Zmym3 promoter fragment increased parallelly in both ChIP assays using antibody against BMI1 or against ubiquitin-H2A in the Bmi1-transfected K562 cells (Fig.5A). Meanwhile, the transcription of Zmym3 was markedly reduced, P < 0.05 (Fig.5B). To further confirm the effect of BMI1 on the expression of ZMYM3, we looked at the transcription of c-fos, one of the ZMYM3 downstream target genes. As being expected, BMI1 increased the transcription of c-fos, in company with a higher level of histone H3 and H3K27 acetylation detected by ChIP and Q-PCR, P < 0.05 (Fig.5C and D). Taken together, these results indicated that BMI1 suppressed ZMYM3 by direct binding to Zmym3 promoter region and enhanced the downstream c-fos pathway in K562 cells by modifying histone acetylation (Tables3).
Affiliation: Key Laboratory of Thrombosis and Hemostasis of Ministry of Health, Jiangsu Institute of Hematology, The First Affiliated Hospital of Soochow University, Soochow, China.