title: Light-mediated regulation defines a minimal promoter region of TOP2.
abstract: Light signaling has been demonstrated to be an important factor for plant growth and development; however, its role in the regulation of DNA replication and cell cycle has just started to be unraveled. In this work, we have demonstrated that the TOP2 promoter of Pisum sativum (pea) is activated by a broad spectrum of light including far-red light (FR), red light (RL) and blue light (BL). Deletion analyses of the TOP2 promoter in transformed plants, Arabidopsis thaliana and Nicotiana tobaccum (tobacco), define a minimal promoter region that is induced by RL, FR and BL, and is essential and sufficient for light-mediated activation. The minimal promoter of TOP2 follows the phytochrome- mediated low-fluence response similar to complex light regulated promoters. DNA-protein interaction studies reveal the presence of a DNA binding activity specific to a 106 bp region of the minimal promoter that is crucial for light-mediated activation. These results altogether indicate a direct involvement of light signaling in the regulation of expression of TOP2, one of the components of the DNA replication/cell cycle machinery.
authors.affiliation: National Center for Plant Genome Research, PO Box 10531, JNU Campus, New Delhi 110067, India.
authors.forename: G H C M
authors.initials: GH
authors.lastname: Hettiarachchi
authors.forename: Vandana
authors.initials: V
authors.lastname: Yadav
authors.forename: M K
authors.initials: MK
authors.lastname: Reddy
authors.forename: Sudip
authors.initials: S
authors.lastname: Chattopadhyay
authors.forename: Sudhir K
authors.initials: SK
authors.lastname: Sopory
mesh_terms: D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics / Q000528:radiation effects; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D002478:Cells, Cultured; D018548:Cotyledon / Q000201:enzymology / Q000235:genetics; D004250:DNA Topoisomerases, Type II / Q000235:genetics* / Q000378:metabolism; D018744:DNA, Plant / Q000235:genetics / Q000378:metabolism; D024202:Electrophoretic Mobility Shift Assay; D015971:Gene Expression Regulation, Enzymologic / Q000528:radiation effects; D018506:Gene Expression Regulation, Plant / Q000528:radiation effects; D005966:Glucuronidase / Q000235:genetics / Q000378:metabolism; D018546:Hypocotyl / Q000201:enzymology / Q000235:genetics; D008027:Light; D008969:Molecular Sequence Data; D009841:Oligonucleotides / Q000235:genetics / Q000378:metabolism; D018532:Pisum sativum / Q000201:enzymology / Q000235:genetics / Q000528:radiation effects; D010834:Phytochrome / Q000378:metabolism; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic / Q000235:genetics*; D011485:Protein Binding; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012045:Regulatory Sequences, Nucleic Acid / Q000235:genetics*; D014026:Nicotiana / Q000166:cytology / Q000201:enzymology / Q000235:genetics / Q000528:radiation effects
chemical_list: D018744:DNA, Plant; D009841:Oligonucleotides; D011993:Recombinant Fusion Proteins; D010834:Phytochrome; D005966:Glucuronidase; D004250:DNA Topoisomerases, Type II