title: Promoter Trapping and Deletion Analysis Show Arabidopsis thaliana APETALA2 Gene Promoter Is Bidirectional and Functions as a Pollen- and Ovule-Specific Promoter in the Reverse Orientation.
abstract: The Arabidopsis thaliana promoter trap mutant Bitrap-112 expressing green fluorescent protein (GFP) gene in the ovules was found to carry transferred DNA (T-DNA) insertion at -309 position of the APETALA2 (AP2) gene. Bitrap-112 line did not show phenotype associated with the AP2 mutation, suggesting that T-DNA insertion did not interrupt the AP2 promoter. Further, head-to-head orientation of GFP and AP2 genes indicated that the AP2 promoter could be bidirectional. A detailed deletion analysis of the upstream sequences of the AP2 gene was done to identify the promoter. GUS assay of transgenic A. thaliana plants carrying various AP2 upstream fragments fused to the uidA gene showed that ~200-bp 5' UTR sequences are capable of driving gene expression at low levels in vegetative tissues whereas inclusion of further upstream sequences (~300 bp) enhanced uidA expression comparable to native AP2 expression levels in various tissues including ovules. In the reverse orientation, the 519-bp AP2 upstream fragment was found to drive gene expression in immature ovules and pollen. Absence of antisense transcripts corresponding to the sequences upstream of AP2 gene in wild-type A. thaliana plants suggests that promoter trapping has uncovered a cryptic promoter, which in reverse orientation is capable of driving gene expression in ovules and anthers.
authors.affiliation: ICAR-National Research Centre on Plant Biotechnology, Pusa Campus, New Delhi, 110012, India.
authors.forename: Pooja
authors.initials: P
authors.lastname: Sharma
authors.affiliation: ICAR-National Research Centre on Plant Biotechnology, Pusa Campus, New Delhi, 110012, India.
authors.forename: Vajinder
authors.initials: V
authors.lastname: Kumar
authors.affiliation: CSIR-Institute of Himalayan Bioresource Technology, Palampur, Himachal Pradesh, 176061, India.
authors.forename: Sunil Kumar
authors.initials: SK
authors.lastname: Singh
authors.affiliation: CSIR-Institute of Himalayan Bioresource Technology, Palampur, Himachal Pradesh, 176061, India.
authors.forename: Shweta
authors.initials: S
authors.lastname: Thakur
authors.affiliation: Chaudhary Devi Lal University, Sirsa, Haryana, 125055, India.
authors.forename: Priyanka
authors.initials: P
authors.lastname: Siwach
authors.affiliation: CSIR-Institute of Himalayan Bioresource Technology, Palampur, Himachal Pradesh, 176061, India.
authors.forename: Yelam
authors.initials: Y
authors.lastname: Sreenivasulu
authors.affiliation: ICAR-National Research Centre on Plant Biotechnology, Pusa Campus, New Delhi, 110012, India.
authors.forename: Ramamurthy
authors.initials: R
authors.lastname: Srinivasan
authors.affiliation: ICAR-National Research Centre on Plant Biotechnology, Pusa Campus, New Delhi, 110012, India. srbhat22@gmail.com.
authors.forename: Shripad Ramachandra
authors.initials: SR
authors.lastname: Bhat
mesh_terms: D020121:5' Untranslated Regions / Q000235:genetics; D017360:Arabidopsis / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000235:genetics*; D003198:Computer Simulation; D018398:Homeodomain Proteins / Q000235:genetics*; D009154:Mutation; D009687:Nuclear Proteins / Q000235:genetics*; D009928:Organ Specificity; D056771:Ovule / Q000235:genetics*; D011058:Pollen / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000235:genetics*; D012343:RNA, Transfer / Q000235:genetics; D017384:Sequence Deletion; D024363:Transcription Initiation Site
chemical_list: D020121:5' Untranslated Regions; C499534:APETALA2 protein, Arabidopsis; D029681:Arabidopsis Proteins; D018398:Homeodomain Proteins; D009687:Nuclear Proteins; D012343:RNA, Transfer
keywords: APETALA2; Bidirectional promoter; GUS; MUG; Promoter trapping; T-DNA