Among the identified VPA-responsive genes, some have been associated previously with NTDs or VPA effects [vinculin, metallothioneins 1 and 2 (Mt1, Mt2), keratin 1-18 (Krt1-18)], whereas others provide novel putative VPA targets, some of which are associated with processes relevant to neural tube formation and closure [transgelin 2 (Tagln2), thyroid hormone receptor interacting protein 6, galectin-1 (Lgals1), inhibitor of DNA binding 1 (Idb1), fatty acid synthase (Fasn), annexins A5 and A11 (Anxa5, Anxa11)], or with VPA effects or known molecular actions of VPA (Lgals1, Mt1, Mt2, Id1, Fasn, Anxa5, Anxa11, Krt1-18).
The similar transcriptional response to VPA in the cell model as in embryos strengthens the case not only for these genes as VPA targets in the embryo but also for a number of other genes (Table 2; Supplemental Material, Tables 1 and 2) such as cytochrome c oxidase subunit VIIa polypeptide 2-like (Cox7a2l), ubiquitin carboxy-terminal hydrolase L1 (Uchl1), eukaryotic translation initiation factor 4 gamma 2 (Eif4g2), bromodomain containing protein 4 (Brd4), annexin A11 (Anxa11), leukotriene B4 12-hydroxydehydrogenase (Ltb4dh), inhibitor of DNA binding 1 (Idb1), and fatty acid synthase (Fasn).
The VPA-induced transcriptional induction of annexin A5 (Anxa5) and Anxa11 we detect in both embryos and cells (Table 2) may depend on HDAC inhibition, as the mouse Anxa5 and the human ANXA11 genes have Sp1 sites in their promoters (Bances et al.
A recurrent theme among these genes, as well as for others (Mt1, Anxa11, Krt1-18), is that they may be activated or repressed through HDAC inhibition and Sp1 activation, indicating that HDAC may be a primary molecular target of VPA action in vivo.
Annexin A11 (ANXA11) gene structure as the progenitor of paralogous annexins and source of orthologous cDNA isoforms.