title: ERK signaling controls blastema cell differentiation during planarian regeneration.
abstract: The robust regenerative ability of planarians depends on a population of somatic stem cells called neoblasts, which are the only mitotic cells in adults and are responsible for blastema formation after amputation. The molecular mechanism underlying neoblast differentiation associated with blastema formation remains unknown. Here, using the planarian Dugesia japonica we found that DjmkpA, a planarian mitogen-activated protein kinase (MAPK) phosphatase-related gene, was specifically expressed in blastema cells in response to increased extracellular signal-related kinase (ERK) activity. Pharmacological and genetic [RNA interference (RNAi)] approaches provided evidence that ERK activity was required for blastema cells to exit the proliferative state and undergo differentiation. By contrast, DjmkpA RNAi induced an increased level of ERK activity and rescued the differentiation defect of blastema cells caused by pharmacological reduction of ERK activity. These observations suggest that ERK signaling plays an instructive role in the cell fate decisions of blastema cells regarding whether to differentiate or not, by inducing DjmkpA as a negative regulator of ERK signaling during planarian regeneration.
authors: Department of Biophysics, Graduate School of Science, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto 606-8502, Japan.
authors: Junichi
authors: J
authors: Tasaki
authors: Norito
authors: N
authors: Shibata
authors: Osamu
authors: O
authors: Nishimura
authors: Kazu
authors: K
authors: Itomi
authors: Yoshimichi
authors: Y
authors: Tabata
authors: Fuyan
authors: F
authors: Son
authors: Nobuko
authors: N
authors: Suzuki
authors: Ryoko
authors: R
authors: Araki
authors: Masumi
authors: M
authors: Abe
authors: Kiyokazu
authors: K
authors: Agata
authors: Yoshihiko
authors: Y
authors: Umesono