title: An egg apparatus-specific enhancer of Arabidopsis, identified by enhancer detection.
abstract: Despite a central role in angiosperm reproduction, few gametophyte-specific genes and promoters have been isolated, particularly for the inaccessible female gametophyte (embryo sac). Using the Ds-based enhancer-detector line ET253, we have cloned an egg apparatus-specific enhancer (EASE) from Arabidopsis (Arabidopsis thaliana). The genomic region flanking the Ds insertion site was further analyzed by examining its capability to control gusA and GFP reporter gene expression in the embryo sac in a transgenic context. Through analysis of a 5' and 3' deletion series in transgenic Arabidopsis, the sequence responsible for egg apparatus-specific expression was delineated to 77 bp. Our data showed that this enhancer is unique in the Arabidopsis genome, is conserved among different accessions, and shows an unusual pattern of sequence variation. This EASE works independently of position and orientation in Arabidopsis but is probably not associated with any nearby gene, suggesting either that it acts over a large distance or that a cryptic element was detected. Embryo-specific ablation in Arabidopsis was achieved by transactivation of a diphtheria toxin gene under the control of the EASE. The potential application of the EASE element and similar control elements as part of an open-source biotechnology toolkit for apomixis is discussed.
authors.affiliation: CAMBIA, Canberra, Australian Capital Territory 2601, Australia.
authors.forename: Wei
authors.initials: W
authors.lastname: Yang
authors.forename: Richard A
authors.initials: RA
authors.lastname: Jefferson
authors.forename: Eric
authors.initials: E
authors.lastname: Huttner
authors.forename: James M
authors.initials: JM
authors.lastname: Moore
authors.forename: Wendy B
authors.initials: WB
authors.lastname: Gagliano
authors.forename: Ueli
authors.initials: U
authors.lastname: Grossniklaus
mesh_terms: D017360:Arabidopsis / Q000196:embryology / Q000235:genetics*; D001483:Base Sequence; D004167:Diphtheria Toxin / Q000235:genetics; D004742:Enhancer Elements, Genetic / Q000235:genetics*; D035264:Flowers / Q000033:anatomy & histology; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant / Q000235:genetics; D017930:Genes, Reporter; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D009928:Organ Specificity; D010063:Ovum / Q000166:cytology / Q000378:metabolism*; D010446:Peptide Fragments / Q000235:genetics; D009195:Peroxidase / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012639:Seeds / Q000166:cytology; D016415:Sequence Alignment; D015533:Transcriptional Activation
chemical_list: D004167:Diphtheria Toxin; D010446:Peptide Fragments; D012333:RNA, Messenger; C029795:diphtheria toxin fragment A; D009195:Peroxidase