DNA methylation: a saga of genome maintenance in hematological perspective.

In recent years, an explosion of interest for genome methylation in hematopoietic stem cells (HSCs) differentiation and transplantation has been observed. The differentiation and timely proliferation of HSCs require a stringent regulation of gene expression; this can't be maintained without the regulation of genome methylation. Evidences of changes in genome methylation patterns in healthy and cancer cells have opened a new paradigm for diagnostic and therapeutic strategies. Genome methylation or DNA methylation is achieved by DNA methyltransferases (DNMTs) through the transfer of methyl group leading to the regulation of gene's expression. Till now five DNMTs have been found in mammals, known as DNMT1, DNMT2, DNMT3A, DNMT3B and DNMT3L. In this review, we have carefully evaluated the spacio-temporal landscape expression and role of DNMTs during hematopoiesis, hematopoietic malignancy and HSCs transplantation. Focusing on the connection of DNA methylation with gene expression in association with cellular signalling, histone modifications, it is proposed for further improvement of strategies to use DNA methylation as a marker in clinical diagnosis as well as in therapeutic interventions by applying DNMTs inhibitors.