title: Membrane water permeability and aquaporin expression increase during growth of maize suspension cultured cells.
abstract: Aquaporins (AQPs) are water channels that allow cells to rapidly alter their membrane water permeability. A convenient model for studying AQP expression and activity regulation is Black Mexican Sweet (BMS) maize cultured cells. In an attempt to correlate membrane osmotic water permeability coefficient (P(f)) with AQP gene expression, we first examined the expression pattern of 33 AQP genes using macro-array hybridization. We detected the expression of 18 different isoforms representing the four AQP subfamilies, i.e. eight plasma membrane (PIP), five tonoplast (TIP), three small basic (SIP) and two NOD26-like (NIP) AQPs. While the expression of most of these genes was constant throughout all growth phases, mRNA levels of ZmPIP1;3, ZmPIP2;1, ZmPIP2;2, ZmPIP2;4 and ZmPIP2;6 increased significantly during the logarithmic growth phase and the beginning of the stationary phase. The use of specific anti-ZmPIP antisera showed that the protein expression pattern correlated well with mRNA levels. Cell pressure probe and protoplast swelling measurements were then performed to determine the P(f). Interestingly, we found that the P(f) were significantly increased at the end of the logarithmic growth phase and during the steady-state phase compared to the lag phase, demonstrating a positive correlation between AQP abundance in the plasma membrane and the cell P(f).
authors.affiliation: Institut des Sciences de la Vie, Université Catholique de Louvain, Louvain-la-Neuve, Belgium.
authors.forename: Menachem
authors.initials: M
authors.lastname: Moshelion
authors.forename: Charles
authors.initials: C
authors.lastname: Hachez
authors.forename: Qing
authors.initials: Q
authors.lastname: Ye
authors.forename: Damien
authors.initials: D
authors.lastname: Cavez
authors.forename: Mohammed
authors.initials: M
authors.lastname: Bajji
authors.forename: Rudolf
authors.initials: R
authors.lastname: Jung
authors.forename: François
authors.initials: F
authors.lastname: Chaumont
mesh_terms: D020346:Aquaporins / Q000235:genetics / Q000378:metabolism*; D002462:Cell Membrane / Q000502:physiology*; D002463:Cell Membrane Permeability; D002478:Cells, Cultured; D018076:DNA, Complementary / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D009995:Osmosis; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D020033:Protein Isoforms; D012333:RNA, Messenger / Q000378:metabolism; D018749:RNA, Plant / Q000235:genetics; D014867:Water / Q000378:metabolism*; D003313:Zea mays / Q000235:genetics / Q000378:metabolism / Q000502:physiology*
chemical_list: D020346:Aquaporins; D018076:DNA, Complementary; D010940:Plant Proteins; D020033:Protein Isoforms; D012333:RNA, Messenger; D018749:RNA, Plant; D014867:Water