Planarian MBD2/3 is required for adult stem cell pluripotency independently of DNA methylation.
Bottom Line: Here we show the planarian methyl-CpG Binding Domain 2/3 (mbd2/3) gene is required for pASC differentiation during regeneration and tissue homeostasis.The genome does not have detectable levels of 5-methylcytosine (5(m)C) and we find no role for a potential DNA methylase.We conclude that MBD proteins may have had an ancient role in broadly controlling animal stem cell pluripotency, but that DNA methylation is not involved in planarian stem cell differentiation.
Affiliation: Department of Zoology, Tinbergen Building, South Parks Road, University of Oxford, Oxford OX1 3PS, United Kingdom.Show MeSH
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Mentions: During tissue homeostasis in intact animals Smed-NB.21.11e+ cells were maintained in mbd2/3(RNAi) animals and accumulated at the sites of anterior regression (Fig. 6A, C and D). On the other hand, later Smed-AGAT-1+ stem cell progeny were depleted in mbd2/3(RNAi) animals (Fig. 6B–D). This resulted in animals with accumulated Smed-NB.21.11e+ cells and depleted Smed-AGAT-1+ cells by 3 weeks of homeostasis (Fig. 6C). The data observed for Smed-NB.21.11e+ and Smed-AGAT-1+ cells was supported by an increase in Smed-NB.21.11e transcript levels and a decrease in Smed-AGAT-1 transcript levels (Supplementary Fig. 4A and B). An alternate early progeny marker Smed-NB.32.1g (Eisenhoffer et al., 2008) was also maintained at the third week of homeostasis following mbd2/3(RNAi) (Fig. 6E). The loss of late neoblast progeny in mbd2/3(RNAi) animals during homeostasis was confirmed using the Smed-CYP1A1 marker gene (Fig. 6F). These data suggest that pASCs lacking mbd2/3 are able to give rise to early stem cell progeny, but that these progeny are unable to differentiate correctly, with later stem cell progeny failing to form.
Affiliation: Department of Zoology, Tinbergen Building, South Parks Road, University of Oxford, Oxford OX1 3PS, United Kingdom.