title: Regulatory gateways for cell-specific gene expression in C4 leaves with Kranz anatomy.
abstract: C4photosynthesis is a carbon-concentrating mechanism that increases delivery of carbon dioxide to RuBisCO and as a consequence reduces photorespiration. The C4pathway is therefore beneficial in environments that promote high photorespiration. This pathway has evolved many times, and involves restricting gene expression to either mesophyll or bundle sheath cells. Here we review the regulatory mechanisms that control cell-preferential expression of genes in the C4cycle. From this analysis, it is clear that the C4pathway has a complex regulatory framework, with control operating at epigenetic, transcriptional, post-transcriptional, translational, and post-translational levels. Some genes of the C4pathway are regulated at multiple levels, and we propose that this ensures robust expression in each cell type. Accumulating evidence suggests that multiple genes of the C4pathway may share the same regulatory mechanism. The control systems for C4photosynthesis gene expression appear to operate in C3plants, and so it appears that pre-existing mechanisms form the basis of C4photosynthesis gene expression.
authors.affiliation: Department of Plant Sciences, Downing Street, University of Cambridge, Cambridge CB2 3EA, UK.
authors.forename: Gregory
authors.initials: G
authors.lastname: Reeves
authors.affiliation: Department of Plant Sciences, Downing Street, University of Cambridge, Cambridge CB2 3EA, UK.
authors.forename: Mathieu J
authors.initials: MJ
authors.lastname: Grangé-Guermente
authors.affiliation: Department of Plant Sciences, Downing Street, University of Cambridge, Cambridge CB2 3EA, UK jmh65@cam.ac.uk.
authors.forename: Julian M
authors.initials: JM
authors.lastname: Hibberd
mesh_terms: D044127:Epigenesis, Genetic; D018506:Gene Expression Regulation, Plant; D010788:Photosynthesis; D018515:Plant Leaves / Q000033:anatomy & histology / Q000378:metabolism*; D010944:Plants / Q000235:genetics / Q000378:metabolism*
keywords: Bundle sheath; C4 photosynthesis; cell specificity; gene regulation; mesophyll.