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XB-ART-54604
Development January 1, 2018; 145 (5):

Phosphorylation states change Otx2 activity for cell proliferation and patterning in the Xenopus embryo.

Satou Y , Minami K , Hosono E , Okada H , Yasuoka Y , Shibano T , Tanaka T , Taira M .


Abstract
The homeodomain transcription factor Otx2 has essential roles in head and eye formation via the negative and positive regulation of its target genes, but it remains elusive how this dual activity of Otx2 affects cellular functions. In the current study, we first demonstrated that both exogenous and endogenous Otx2 are phosphorylated at multiple sites. Using Xenopus embryos, we identified three possible cyclin-dependent kinase (Cdk) sites and one Akt site, and analyzed the biological activities of phosphomimetic (4E) and nonphosphorylatable (4A) mutants for those sites. In the neuroectoderm, the 4E but not the 4A mutant downregulated the Cdk inhibitor gene p27xic1 (cdknx) and posterior genes, and promoted cell proliferation, possibly forming a positive-feedback loop consisting of Cdk, Otx2 and p27xic1 for cell proliferation, together with anteriorization. Conversely, the 4A mutant functioned as an activator on its own and upregulated the expression of eye marker genes, resulting in enlarged eyes. Consistent with these results, the interaction of Otx2 with the corepressor Tle1 is suggested to be phosphorylation dependent. These data suggest that Otx2 orchestrates cell proliferation, anteroposterior patterning and eye formation via its phosphorylation state.

PubMed ID: 29440302
Article link: Development

Genes referenced: akt1 cdknx gbx2.1 gbx2.2 gsc mapk1 meis3 muc2 myc otx2 pax2 pax6 rax tle1
GO keywords: cell proliferation [+]


Article Images: [+] show captions


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