| Abstract |
DNA methylation is essential for embryonic development as well as in diverse biological
processes. The DNA methyltransferase Dnmt1 is responsible for maintaining the methylation
patterns on daughter strands after DNA replication, but it is also known for mediating
repression. DNMT1 knock out/down (KO/KD) studies in hematopoietic lineages or in mice,
revealed that DNMT1 drives HSCs to myeloerythroid fate. Previous publications of our
laboratory showed that DNMT1 interacts with several erythroid transcription factors (GATA1,
FOG-1, GFI-1b) forming a core complex composed by DNMT1 and transcription factors ZBP89
and ZNF143, which interacts with distinct hematopoietic protein subcomplexes. Additionally,
the PCNA Binding domain (PBD) of DNMT1 proved necessary and sufficient for DNMT1
interaction with these transcription factors. Moreover, DNMT1 KD experiments in murine
erythroleukemic (MEL) cells revealed defects in cell cycle arrest in erythroid differentiation
due to impaired repression of genes responsible for cell proliferation. The main aim of this
study is to further elucidate the role of DNMT1 in erythroid cell differentiation. To these ends,
I carried out a phenotypic characterization of DNMT1 KO MEL cells previously generated by
CRISPR/Cas9. It was found that DNMT1 KO cells display a phenotype similar to the knockdown
experiments concerning cell cycle progression and impaired erythroid differentiation.
In addition, previous studies showed that DNMT1 is involved in the repression of γ-globin
gene expression in adult-stage erythroid cells by methylating its promoter. Furthermore,
several studies have suggested that DNMT1 associates directly or indirectly with BCL11A, a
factor known to be responsible for silencing the expression of mouse embryonic b-like globins
(εy and βh1) as well as of the human γ-globin gene. Following these data, we investigated the
DNMT1 interactions with BCL11A, our hypothesis being that DNMT1 acts as a co-repressor of
these genes during erythropoiesis.
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Characterization of the molecular functions of the DNA methyltransferase 1, DNMT1 in erythropoiesis
