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Res Rep Gynaecol Obstet 2017 | Volume 1 Issue 4
November 02-03, 2017 | Chicago, USA
Embryology and In vitro Fertilization
World Congress on
T
he process of brain development encompasses different
stages of neurogenesis, migration, differentiation,
apoptosis, arborization, synaptogenesis, synaptic sculpting
and myelination. Neural stem cells (NSCs) that transform
from neuroepithelial cells have a multipotential ability to
give rise to neurons and glial cells, that is, astrocytes and
oligodendrocytes. Differentiation of NSCs that line the neural
tube is tightly regulated spatiotemporally by many genetic
factors and epigenetic modi cations, which can interact
with transcription factors and environmental factors.
Epigenetics modi cations in uence genes activation and
silencing at different steps of NSCs differentiation through
DNA methylation, histone modi cation, and non-coding
RNAs expression without changes in the DNA sequence.
Neuronal differentiation in mid-gestation, which precedes
glial differentiation, is induced by epigenetic mechanisms
through regulation of neurogenic basic helix-loop-helix
(bHLH) transcription factors such as Ngn1, Ngn2, and Mash1.
Thereafter, at late gestation, DNA methylation in astrocyte-
specific promoter results in glial cells differentiation. So,
DNA methylation is one of the essential epigenetic factors
in differentiation of NSCs during development. DNA
methylation is carried out through cytosine methylation of
genomic DNA at CpG dinucleotides, which directly interferes
with the binding of transcription factors to the target
sequences by a family of DNA methyltransferases (DNMTs).
The DNMTs family is essential for embryogenesis as their
functions are necessary for maintenance of methylation
patterns during DNA replication (DNMT1), and for
de novo
methylation (DNMT3a and DNMT3b). Histone modi cation
is very complex epigenetic mechanism compared with
DNA methylation. H3 and H4 core histones are modified by
methylation, acetylation of lysine residue, phosphorylation,
ubiquitylation, glycosylation, biotinylation, carbonylation
and ADP-ribosylation. Non-coding RNAs such as microRNAs
and long non-coding RNA also play roles in gene expression
by transcriptional and post-transcriptional regulation, so
affects the sequential differentiation of NSCs during brain
development. In this seminar, the author would like to
discuss epigenetic mechanisms such as DNA methylation,
histone modi cation, and non-coding RNAs expression that
are involved in the differentiation of neural stem cells in the
developing brain.
e:
isaabdirad@yahoo.comEpigenetic mechanisms in the differentiation of neural stem cells in the developing brain
Isa Abdi Rad
Urmia University of Medical Sciences, Iran