title: Functional conservation of MIKC*-Type MADS box genes in Arabidopsis and rice pollen maturation.
abstract: There are two groups of MADS intervening keratin-like and C-terminal (MIKC)-type MADS box genes, MIKC(C) type and MIKC* type. In seed plants, the MIKC(C) type shows considerable diversity, but the MIKC* type has only two subgroups, P- and S-clade, which show conserved expression in the gametophyte. To examine the functional conservation of MIKC*-type genes, we characterized all three rice (Oryza sativa) MIKC*-type genes. All three genes are specifically expressed late in pollen development. The single knockdown or knockout lines, respectively, of the S-clade MADS62 and MADS63 did not show a mutant phenotype, but lines in which both S-clade genes were affected showed severe defects in pollen maturation and germination, as did knockdown lines of MADS68, the only P-clade gene in rice. The rice MIKC*-type proteins form strong heterodimeric complexes solely with partners from the other subclade; these complexes specifically bind to N10-type C-A-rich-G-boxes in vitro and regulate downstream gene expression by binding to N10-type promoter motifs. The rice MIKC* genes have a much lower degree of functional redundancy than the Arabidopsis thaliana MIKC* genes. Nevertheless, our data indicate that the function of heterodimeric MIKC*-type protein complexes in pollen development has been conserved since the divergence of monocots and eudicots, roughly 150 million years ago.
authors.affiliation: Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Liu
authors.forename: Shaojie
authors.initials: S
authors.lastname: Cui
authors.forename: Feng
authors.initials: F
authors.lastname: Wu
authors.forename: Shuo
authors.initials: S
authors.lastname: Yan
authors.forename: Xuelei
authors.initials: X
authors.lastname: Lin
authors.forename: Xiaoqiu
authors.initials: X
authors.lastname: Du
authors.forename: Kang
authors.initials: K
authors.lastname: Chong
authors.forename: Susanne
authors.initials: S
authors.lastname: Schilling
authors.forename: Günter
authors.initials: G
authors.lastname: Theißen
authors.forename: Zheng
authors.initials: Z
authors.lastname: Meng
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D005966:Glucuronidase / Q000235:genetics / Q000378:metabolism; D017403:In Situ Hybridization; D026161:MADS Domain Proteins / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D046529:Microscopy, Electron, Transmission; D012275:Oryza / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D030821:Plants, Genetically Modified; D011058:Pollen / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D053205:Pollen Tube / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure; D011485:Protein Binding; D011523:Protoplasts / Q000378:metabolism; D034622:RNA Interference; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D029681:Arabidopsis Proteins; D026161:MADS Domain Proteins; D010940:Plant Proteins; D005966:Glucuronidase