title: Family business: the multidrug-resistance related protein (MRP) ABC transporter genes in Arabidopsis thaliana.
abstract: Despite the completion of the sequencing of the entire genome of Arabidopsis thaliana (L.) Heynh., the exact determination of each single gene and its function remains an open question. This is especially true for multigene families. An approach that combines analysis of genomic structure, expression data and functional genomics to ascertain the role of the members of the multidrug-resistance-related protein ( MRP) gene family, a subfamily of the ATP-binding cassette (ABC) transporters from Arabidopsis is presented. We used cDNA sequencing and alignment-based re-annotation of genomic sequences to define the exact genic structure of all known AtMRP genes. Analysis of promoter regions suggested different induction conditions even for closely related genes. Expression analysis for the entire gene family confirmed these assumptions. Phylogenetic analysis and determination of segmental duplication in the regions of AtMRP genes revealed that the evolution of the extraordinarily high number of ABC transporter genes in plants cannot solely be explained by polyploidisation during the evolution of the Arabidopsis genome. Interestingly MRP genes from Oryza sativa L. (rice; OsMRP) show very similar genomic structures to those from Arabidopsis. Screening of large populations of T-DNA-mutagenised lines of A. thaliana resulted in the isolation of AtMRP insertion mutants. This work opens the way for the defined analysis of a multigene family of important membrane transporters whose broad variety of functions expands their traditional role as cellular detoxifiers.
authors.affiliation: Universität zu Köln, Botanik II (AG Flügge), Max-Delbrück-Laboratorium in der Max-Planck-Gesellschaft, Germany.
authors.forename: H Uner
authors.initials: HU
authors.lastname: Kolukisaoglu
authors.forename: Lucien
authors.initials: L
authors.lastname: Bovet
authors.forename: Markus
authors.initials: M
authors.lastname: Klein
authors.forename: Thomas
authors.initials: T
authors.lastname: Eggmann
authors.forename: Markus
authors.initials: M
authors.lastname: Geisler
authors.forename: Dierk
authors.initials: D
authors.lastname: Wanke
authors.forename: Enrico
authors.initials: E
authors.lastname: Martinoia
authors.forename: Burkhard
authors.initials: B
authors.lastname: Schulz
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000235:genetics* / Q000378:metabolism; D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D002874:Chromosome Mapping; D018432:Drug Resistance, Multiple / Q000235:genetics; D019143:Evolution, Molecular; D018506:Gene Expression Regulation, Plant / Q000235:genetics; D018745:Genome, Plant; D008969:Molecular Sequence Data; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000235:genetics / Q000378:metabolism; D005810:Multigene Family / Q000235:genetics; D010802:Phylogeny; D011401:Promoter Regions, Genetic / Q000235:genetics; D011544:Pseudogenes / Q000235:genetics; D015854:Up-Regulation / Q000235:genetics
chemical_list: D018528:ATP-Binding Cassette Transporters; D029681:Arabidopsis Proteins; D027425:ATP-Binding Cassette, Sub-Family C Proteins