title: AGAMOUS-LIKE13, a putative ancestor for the E functional genes, specifies male and female gametophyte morphogenesis.
abstract: Arabidopsis AGL13 is a member of the AGL6 clade of the MADS box gene family. GUS activity was specifically detected from the initiation to maturation of both pollen and ovules in AGL13:GUS Arabidopsis. The sterility of the flower with defective pollen and ovules was found in AGL13 RNAi knockdown and AGL13 + SRDX dominant-negative mutants. These results indicate that AGL13 acts as an activator in regulation of early initiation and further development of pollen and ovules. The production of similar floral organ defects in the severe AGL13 + SRDX and SEP2 + SRDX plants and the similar enhancement of AG nuclear localization efficiency by AGL13 and SEP3 proteins suggest a similar function for AGL13 and E functional SEP proteins. Additional fluorescence resonance energy transfer (FRET) analysis indicated that, similar to SEP proteins, AGL13 is able to interact with AG to form quartet-like complexes (AGL13-AG)2 and interact with AG-AP3-PI to form a higher-order heterotetrameric complex (AGL13-AG-AP3-PI). Through these complexes, AGL13 and AG could regulate the expression of similar downstream genes involved in pollen morphogenesis, anther cell layer formation and the ovule development. AGL13 also regulates AG/AP3/PI expression by positive regulatory feedback loops and suppresses its own expression through negative regulatory feedback loops by activating AGL6, which acts as a repressor of AGL13. Our data suggest that AGL13 is likely a putative ancestor for the E functional genes which specifies male and female gametophyte morphogenesis in plants during evolution.
authors.affiliation: Institute of Biotechnology, National Chung Hsing University, Taichung, 40227, Taiwan.
authors.forename: Wei-Han
authors.initials: WH
authors.lastname: Hsu
authors.forename: Tsung-Jen
authors.initials: TJ
authors.lastname: Yeh
authors.forename: Kai-Yu
authors.initials: KY
authors.lastname: Huang
authors.forename: Jen-Ying
authors.initials: JY
authors.lastname: Li
authors.forename: Hsing-Yu
authors.initials: HY
authors.lastname: Chen
authors.forename: Chang-Hsien
authors.initials: CH
authors.lastname: Yang
mesh_terms: D017360:Arabidopsis / Q000166:cytology / Q000235:genetics* / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D035264:Flowers / Q000166:cytology / Q000235:genetics / Q000254:growth & development; D015870:Gene Expression; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D017930:Genes, Reporter; D026161:MADS Domain Proteins / Q000235:genetics / Q000378:metabolism; D008954:Models, Biological; D009154:Mutation; D009928:Organ Specificity; D056771:Ovule / Q000166:cytology / Q000235:genetics / Q000254:growth & development; D010641:Phenotype; D030821:Plants, Genetically Modified; D011058:Pollen / Q000166:cytology / Q000235:genetics / Q000254:growth & development; D055503:Protein Multimerization; D034622:RNA Interference
chemical_list: C000593712:AGL13 protein, Arabidopsis; D029681:Arabidopsis Proteins; D026161:MADS Domain Proteins
keywords: AGAMOUS-LIKE13; MADS box gene; fluorescence resonance energy transfer; heterotetrameric protein complex; pollen morphogenesis