Neural crest fate is affected by folate deficiency through reduction of methylation on sox2 locus.

ALATA JIMENEZ, NAGIF; SANCHEZ-VASQUEZ, E.; STROBL MAZZULLA, P.H.

Congreso; X International Meeting of the Latin American Society for Developmental Biology; 2019

Folate deficiency has been known to contribute to neural tube and neural crest defects, but why these tissues are particularly affected, and which are the molecular mechanisms involved in those abnormalities are importanthuman health questions that remain unanswered. Here we study the function of two of the main folate transporters, FolR1 and Rfc1, which are robustly expressed in these tissues. Folate is the precursor of Sadenosylmethionine, which is the main donor for DNA, protein and RNA methylation. Our results show that knockdown of FolR1 and/or Rfc1 reduced the abundance of histone H3 lysine and DNA  methylation, two epigenetic modifications that play an important role during neural and neural crest development. Additionally, by knocking down folate transporter or pharmacologically inhibiting folate transport and metabolism, we observed ectopic Sox2 expression at the expense of neural crest markers in the dorsal neural tube. This is correlated with neural crest associated defects, with particular impact on orofacial formation. By using bisulfite sequencing, we show that this phenotype is consequence of reduced DNA methylation on the Sox2 locus at the dorsal neural tube, which can be rescued by the addition of folinic acid. Taken together, our in vivo results reveal the importance of folate as a source of the methyl groups necessary for the establishment of the correct epigenetic marks during neural and neural crest fate-restriction.