Protein Serine/Threonine Phosphotase-1 is Essential in Governing Normal Development of Vertebrate Eye

W.-F.      Hu; D.W.-C.      Li; S.-J.      Liu; Y.-Z.      Liu; M.-B.      Yu; L.-X.      Luo; X.-L.      Liu; M.-X.      Wu; K.-L.      Wu; Z.      Woodward; W.-B.      Liu; X.-H.      Hu; W.-K.      Ji; X.-W.      Zhang; L.      Nie; J.      Liu; H.-G.      Chen; X.-C.      Tang; F.-Y.      Liu; Q.      Yan

Abstract

Protein serine/threonine phosphatase-1 (PP-1) is one of the key enzymes responsible for dephosphorylation in vertebrates. Protein dephosphorylation via PP-1 is implicated in many different biological processes including gene expression, cell cycle control, transformation, neuronal transmission, apoptosis, autophage and senescence. However, whether PP-1 directly controls animal development remains to be investigated. Here, we present direct evidence to show that PP-1 plays an essential role in regulating eye development of vertebrates. Using goldfish as a model system, we have shown the following novel results. First, inhibition of PP-1 activity leads to death of a majority of the treated embryos, and the survived embryos displayed severe phenotype in the eye. Second, knockdown of each catalytic subunit of PP-1 with morpholino oligomers leads to partial (PP-lα knockdown) or complete (PP-lβ or PP-lγ knockdown) death of the injected embryos. The survived embryos from PP-1α knockdown displayed clear retardation in lens differentiation. Finally, overexpression of each subunit of PP-1 also causes death of majority of the injected embryos and leads to abnormal development of goldfish eye. Mechanistically, Pax-6 is one of the major downstream targets mediating the effects of PP-1 function since the eye phenotype in Pax-6 knockdown fish is similar to that derived from overexpression of PP-1. Together, our results for the first time provide direct evidence that protein phosphatase-1 plays a key role in governing normal eye formation during goldfish development.

Keywords: Cataract, differentiation, eye development, lens, PP-1, PP-1α/β/γ, protein phosphatases, retina, retina degeneration, gene expression, cell cycle progression, transformation, neuronal transmission, apoptosis, autophage