DNA methylation-mediated silencing of PU.1 in leukemia cells resistant to cell differentiation

Autor: Francisco S. Torres, Zunilda Sánchez, Estefanía Monturus, Pablo E. Hernández, Agustín F. Fernández, María José Fernández-Nestosa, Jorge Bernardo Schvartzman, Mario F. Fraga, Dora B. Krimer
Přispěvatelé: DNA methylation
Rok vydání: 2013
Předmět:
Zdroj: SpringerPlus
Digital.CSIC. Repositorio Institucional del CSIC
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ISSN: 2193-1801
Popis: In mice, the proviral integration of the Friend Spleen Focus Forming Virus (SFFV) within the PU.1 locus of erythroid precursors results in the development of erythroleukemia. SFFV integrates several kilobases upstream of the PU.1 transcription initiation start site leading to the constitutive activation of the gene which in turn results in a block of erythroid differentiation. In this study we have mapped and sequenced the exact location of the retroviral integration site. We have shown that SFFV integrates downstream of a previously described upstream regulatory element (URE), precisely 2,976 bp downstream of the URE-distal element. We have also found that SFFV persists integrated within the same location in resistant cell lines that have lost their differentiation capacity and in which case PU.1 remains silent. We have examined the methylation status of PU.1 and found that in resistant cells the nearby CpG islands remained methylated in contrast to a non-methylated status of the parental cell lines. Treatment with 5-aza-2′-deoxycytidine caused resistant cells to differentiate yet only when combined with HMBA. Altogether these results strongly suggest that methylation plays a crucial role with regard to PU.1 silencing. However, although demethylation is required, it is not sufficient to overcome the differentiation impasse. We have also showed that activation blockage of the Epo/Epo-R pathway remains despite of the absence of PU.1.
This work was supported by grants BFU2011-22489 from the Spanish Ministerio de Economia y Competitividad, AP/038170/11 from the AECI, Agencia Española de Cooperación Internacional and I-COOP0009 from the Agencia Estatal CSIC. MJFN was a recipient of a fellowship from the CONACYT, Paraguay.
Erythroleukemia cells
Databáze: OpenAIRE