title: The zebrafish homologs of SET/I2PP2A oncoprotein: expression patterns and insights into their physiological roles during development.
abstract: The oncoprotein SET/I2PP2A (protein phosphatase 2A inhibitor 2) participates in various cellular mechanisms such as transcription, cell cycle regulation and cell migration. SET is also an inhibitor of the serine/threonine phosphatase PP2A, which is involved in the regulation of cell homeostasis. In zebrafish, there are two paralogous set genes that encode Seta (269 amino acids) and Setb (275 amino acids) proteins which share 94% identity. We show here that seta and setb are similarly expressed in the eye, the otic vesicle, the brain and the lateral line system, as indicated by in situ hybridization labeling. Whole-mount immunofluorescence analysis revealed the expression of Seta/b proteins in the eye retina, the olfactory pit and the lateral line neuromasts. Loss-of-function studies using antisense morpholino oligonucleotides targeting both seta and setb genes (MOab) resulted in increased apoptosis, reduced cell proliferation and morphological defects. The morphant phenotypes were partially rescued when MOab was co-injected with human SET mRNA. Knockdown of setb with a transcription-blocking morpholino oligonucleotide (MOb) resulted in phenotypic defects comparable with those induced by setb gRNA (guide RNA)/Cas9 [CRISPR (clustered regularly interspaced short palindromic repeats)-associated 9] injections. In vivo labeling of hair cells showed a significantly decreased number of neuromasts in MOab-, MOb- and gRNA/Cas9-injected embryos. Microarray analysis of MOab morphant transcriptome revealed differential expression in gene networks controlling transcription in the sensory organs, including the eye retina, the ear and the lateral line. Collectively, our results suggest that seta and setb are required during embryogenesis and play roles in the zebrafish sensory system development.
authors.affiliation: Laboratory of Biological Chemistry, Medical School, University of Ioannina, Ioannina, Greece.|Division of Biomedical Research, Foundation for Research and Technology-Hellas, Institute of Molecular Biology and Biotechnology, Ioannina, Greece.
authors.forename: Iliana
authors.initials: I
authors.lastname: Serifi
authors.affiliation: Laboratory of Biological Chemistry, Medical School, University of Ioannina, Ioannina, Greece.|Division of Biomedical Research, Foundation for Research and Technology-Hellas, Institute of Molecular Biology and Biotechnology, Ioannina, Greece.
authors.forename: Eleni
authors.initials: E
authors.lastname: Tzima
authors.affiliation: Laboratory of Biological Chemistry, Medical School, University of Ioannina, Ioannina, Greece.|Division of Biomedical Research, Foundation for Research and Technology-Hellas, Institute of Molecular Biology and Biotechnology, Ioannina, Greece.
authors.forename: Katerina
authors.initials: K
authors.lastname: Soupsana
authors.affiliation: Laboratory of Biological Chemistry, Medical School, University of Ioannina, Ioannina, Greece.
authors.forename: Zoe
authors.initials: Z
authors.lastname: Karetsou
authors.affiliation: Developmental Biology, Biomedical Research Foundation Academy of Athens, Athens, Greece.
authors.forename: Dimitris
authors.initials: D
authors.lastname: Beis
authors.affiliation: Laboratory of Biological Chemistry, Medical School, University of Ioannina, Ioannina, Greece.|Division of Biomedical Research, Foundation for Research and Technology-Hellas, Institute of Molecular Biology and Biotechnology, Ioannina, Greece.
authors.forename: Thomais
authors.initials: T
authors.lastname: Papamarcaki
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D015153:Blotting, Western; D001921:Brain / Q000196:embryology / Q000378:metabolism; D004625:Embryo, Nonmammalian / Q000378:metabolism; D005123:Eye / Q000196:embryology / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental / Q000235:genetics / Q000502:physiology; D017403:In Situ Hybridization; D008969:Molecular Sequence Data; D060888:Real-Time Polymerase Chain Reaction; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D015027:Zebrafish; D029961:Zebrafish Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D014157:Transcription Factors; D029961:Zebrafish Proteins
keywords: SET/I2PP2A; neuromasts; retinal ganglion cell|rgc; sensory system; zebrafish