Mps1 (Monopolar Spindle 1) Protein Inhibition Affects Cellular Growth and Pro-Embryogenic Masses Morphology in Embryogenic Cultures of Araucaria angustifolia (Araucariaceae)

PLOS ONE, Dec 2019

Somatic embryogenesis has been shown to be an efficient tool for studying processes based on cell growth and development. The fine regulation of the cell cycle is essential for proper embryo formation during the process of somatic embryogenesis. The aims of the present work were to identify and perform a structural and functional characterization of Mps1 and to analyze the effects of the inhibition of this protein on cellular growth and pro-embryogenic mass (PEM) morphology in embryogenic cultures of A. angustifolia. A single-copy Mps1 gene named AaMps1 was retrieved from the A. angustifolia transcriptome database, and through a mass spectrometry approach, AaMps1 was identified and quantified in embryogenic cultures. The Mps1 inhibitor SP600125 (10 μM) inhibited cellular growth and changed PEMs, and these effects were accompanied by a reduction in AaMps1 protein levels in embryogenic cultures. Our work has identified the Mps1 protein in a gymnosperm species for the first time, and we have shown that inhibiting Mps1 affects cellular growth and PEM differentiation during A. angustifolia somatic embryogenesis. These data will be useful for better understanding cell cycle control during somatic embryogenesis in plants.

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Mps1 (Monopolar Spindle 1) Protein Inhibition Affects Cellular Growth and Pro-Embryogenic Masses Morphology in Embryogenic Cultures of Araucaria angustifolia (Araucariaceae)

April Mps1 (Monopolar Spindle 1) Protein Inhibition Affects Cellular Growth and Pro- Embryogenic Masses Morphology in Embryogenic Cultures of Araucaria angustifolia (Araucariaceae) Jackellinne C. Douétts-Peres 1 2 Marco Antônio L. Cruz 0 2 Ricardo S. Reis 2 Angelo S. Heringer 2 Eduardo A. G. de Oliveira 0 2 Paula M. Elbl 2 Eny I. S. Floh 2 Vanildo Silveira 2 Claudete Santa-Catarina 1 2 0 Laboratório de Biotecnologia Vegetal, Núcleo em Ecologia e Desenvolvimento Sócio-ambiental de Macaé, Universidade Federal do Rio de Janeiro , Macaé, Rio de Janeiro, Brazil, 3 Laboratório de Biotecnologia, CBB, UENF, Campos dos Goytacazes, Rio de Janeiro , Brazil , 4 Unidade de Biologia Integrativa , Setor de Proteômica, UENF, Campos dos Goytacazes, Rio de Janeiro , Brazil , 5 Laboratório de Biologia Celular de Plantas, Departamento de Botânica, Instituto de Biociências, Universidade de São Paulo , São Paulo, São Paulo , Brazil 1 Laboratório de Biologia Celular e Tecidual, Centro de Biociências e Biotecnologia (CBB), Universidade Estadual do Norte Fluminense Darcy Ribeiro (UENF) , Campos dos Goytacazes, Rio de Janeiro , Brazil 2 Editor: Michael Polymenis, Texas A&M University , UNITED STATES Somatic embryogenesis has been shown to be an efficient tool for studying processes based on cell growth and development. The fine regulation of the cell cycle is essential for proper embryo formation during the process of somatic embryogenesis. The aims of the present work were to identify and perform a structural and functional characterization of Mps1 and to analyze the effects of the inhibition of this protein on cellular growth and proembryogenic mass (PEM) morphology in embryogenic cultures of A. angustifolia. A singlecopy Mps1 gene named AaMps1 was retrieved from the A. angustifolia transcriptome database, and through a mass spectrometry approach, AaMps1 was identified and quantified in embryogenic cultures. The Mps1 inhibitor SP600125 (10 μM) inhibited cellular growth and changed PEMs, and these effects were accompanied by a reduction in AaMps1 protein levels in embryogenic cultures. Our work has identified the Mps1 protein in a gymnosperm species for the first time, and we have shown that inhibiting Mps1 affects cellular growth and PEM differentiation during A. angustifolia somatic embryogenesis. These data will be useful for better understanding cell cycle control during somatic embryogenesis in plants. - OPEN ACCESS Data Availability Statement: All relevant data are within the paper and its Supporting Information files. Introduction The transition from a somatic cell into a somatic embryo, during somatic embryogenesis, is a complex event, consisting of the following crucial steps: induction, cell dedifferentiation, and competence acquisition; multiplication, with intense cell division; maturation, which determines fate; and the germination of somatic embryos [ 1 ]. During somatic embryo formation, the correct performance of the cell cycle is crucial, and adequate levels of certain signaling molecules, such as polyamines, carbohydrates, and nitric oxide (NO), are required [ 2–4 ]. The maturation induction of somatic embryogenic cultures with maturation promoters, such as abscisic acid (ABA), or with osmotic agents, such as polyethylene glycol (PEG) and maltose, induce cell growth inhibition, preventing division and promoting the differentiation of cell cultures [ 5–8 ]. However, other compounds, such as auxins, NO, and putrescine, promote cell division, thereby increasing growth and inhibiting cell differentiation into somatic embryos [ 4,6,7 ]. Embryogenic suspension culture systems have been developed for Araucaria angustifolia, and they have been shown to be efficient systems for studying the effects of signaling molecules in gymnosperms [ 4,9,10 ]. Cell cycle regulation can be used as a tool for the elucidation of metabolism-related events, and it involves signaling compounds that are important for various processes in plant development [11], including somatic embryogenesis [ 12 ]. Cell division in eukaryotes is controlled by a complex mechanism that involves cyclindependent kinases (CDKs) as key regulators [ 13,14 ]. One of these kinases is Mps1 (monopolar spindle 1), which has been described in humans and is characterized as a cell cycle regulator that is evolutionarily conserved in eukaryotes [15]. Mps1 is a dual-specificity protein kinase that plays a critical role in monitoring the accuracy of chromosome segregation at the mitotic checkpoint, and it is an important component of the spindle assembly checkpoint (SAC) [ 16 ]. Among chemical inhibitors, SP600125 acts on Jun N-terminal kinase (JNK) proteins in humans [ 17 ] and has been valuable in validating the cellular functions of Mps1. In plants, a protein was found that was highly similar to human Mps1 in terms of structural characteristics, such as its catalytic site, and it was conserved relative to the Mps1 protein found i (...truncated)


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Jackellinne C. Douétts-Peres, Marco Antônio L. Cruz, Ricardo S. Reis, Angelo S. Heringer, Eduardo A. G. de Oliveira, Paula M. Elbl, Eny I. S. Floh, Vanildo Silveira, Claudete Santa-Catarina. Mps1 (Monopolar Spindle 1) Protein Inhibition Affects Cellular Growth and Pro-Embryogenic Masses Morphology in Embryogenic Cultures of Araucaria angustifolia (Araucariaceae), PLOS ONE, 2016, Volume 11, Issue 4, DOI: 10.1371/journal.pone.0153528