title: Mitogen-activated protein kinases are developmentally regulated during stress-induced microspore embryogenesis in Brassica napus L.
abstract: Plant mitogen-activated protein kinase (MAPK) cascades are involved in extracellular stress signalling pathways, leading to different cellular responses. Stress-induced microspore embryogenesis involves the internalization of an extracellular stress signal, generating a number of cellular responses where MAPK cascades might be involved. These responses include a change of the developmental programme, the entry into an early proliferative stage and, subsequently, into differentiation stages during haploid embryogenesis. In this work we studied the expression during microspore embryogenesis of several kinases, to assess their putative role in these events. The known Brassica napus MAP kinase kinase kinases (MAP3Ks BnMAP3Kalpha1, BnMAP3Kbeta1 and BnMAP3Kepsilon, the BnBSKtheta kinase and B. napus extracellular signal-regulated kinase (ERK) homologues were analysed by electron microscope (EM) in situ hybridization, immuno-gold labelling, immunofluorescence and western blotting. The differential in situ expression of these kinases suggests a role for them during embryogenesis. Two different expression patterns were observed, indicating a different regulation. BnMAP3Kalpha1, BnMAP3Kepsilon, and the ERKs showed a pattern consistent with a role mainly in proliferative events. Conversely, BnMAP3Kbeta1 and BnBSKtheta, presented a pattern that suggested an involvement in differentiation stages. In addition, ERK homologues migrate to the nucleus immediately after induction, being found in a phosphorylated state in a larger amount.
authors.affiliation: Plant Development and Nuclear Organization Unit, Centro de Investigaciones Biológicas-C.S.I.C. C, Ramiro de Maeztu 9, 28040 Madrid, Spain.
authors.forename: José M
authors.initials: JM
authors.lastname: Seguí-Simarro
authors.forename: Pilar S
authors.initials: PS
authors.lastname: Testillano
authors.forename: Stefan
authors.initials: S
authors.lastname: Jouannic
authors.forename: Yves
authors.initials: Y
authors.lastname: Henry
authors.forename: Maria C
authors.initials: MC
authors.lastname: Risueño
mesh_terms: D015153:Blotting, Western; D029688:Brassica napus / Q000166:cytology / Q000196:embryology* / Q000201:enzymology; D018929:Cell Culture Techniques; D005455:Fluorescent Antibody Technique; D018507:Gene Expression Regulation, Developmental; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D006238:Haploidy; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D016253:Microscopy, Immunoelectron; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics* / Q000378:metabolism; D010766:Phosphorylation; D011058:Pollen / Q000196:embryology* / Q000201:enzymology / Q000648:ultrastructure; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D013696:Temperature
chemical_list: D012333:RNA, Messenger; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases