title: Effect of overexpression of Arabidopsis damaged DNA-binding protein 1A on de-etiolated 1.
abstract: In Arabidopsis thaliana, de-etiolated 1 mutants (det1) grown in the dark resemble light-grown wild-type seedlings. Arabidopsis DET1 encodes a 62 kD protein, which is a negative regulator of light signaling. UV-damaged DNA-binding protein 1 (DDB1) was initially identified due to its role in human DNA damage repair. Arabidopsis has two DDB1 homologs: DDB1A and DDB1B. DDB1A mutation enhances det1 mutant phenotypes. In this study, we generated Arabidopsis lines that overexpress DDB1A-3HA in wild-type, det1, as well as Myc-DET1 or GFP-DET1 rescued genetic backgrounds. DDB1A-3HA overexpression resulted in decreased apical hook formation in wild-type dark-grown seedlings, and enhanced det1 small rosette and early flowering time phenotypes. In the Myc-DET1 background, DDB1A-3HA overexpression resulted in decreased rescue of dark- and light-grown hypocotyl length, light-grown anthocyanin and chlorophyll levels, adult height and stem number phenotypes. This result is consistent with the decreased levels of Myc-DET1 protein detected in the DDB1A-3HA overexpression line. The GFP-DET1 DDB1A-3HA double overexpression line exhibited increased rescue of dark and light-grown hypocotyl length and light-grown chlorophyll level phenotypes relative to GFP-DET1 alone, despite the fact that GFP-DET1 protein also decreased in the double overexpression line. In addition, increased DET1 resulted in decreased DDB1A-3HA levels due to proteasomal degradation. Overall, DDB1A-3HA overexpression affected phenotypes in a variety of DET1 backgrounds, reduced epitope-tagged DET1 levels, and, correlatively, in general dampened the rescue of det1 mutants by the DET1-DDB1A complex.
authors.affiliation: Department of Biological Sciences, University of Manitoba, Winnipeg, MB R3T 2N2, Canada.
authors.forename: Yu
authors.initials: Y
authors.lastname: Zhang
authors.forename: Dana Frances
authors.initials: DF
authors.lastname: Schroeder
mesh_terms: D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D002850:Chromatography, Gel; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D003624:Darkness; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D049452:Green Fluorescent Proteins / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins; D007976:Leupeptins / Q000494:pharmacology; D009687:Nuclear Proteins / Q000378:metabolism*; D010641:Phenotype; D061988:Proteasome Inhibitors; D011485:Protein Binding / Q000187:drug effects; D021381:Protein Transport / Q000187:drug effects; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D036226:Seedlings / Q000187:drug effects / Q000235:genetics / Q000254:growth & development
chemical_list: D029681:Arabidopsis Proteins; C517426:DDB1a protein, Arabidopsis; C088435:DET1 protein, Arabidopsis; D004268:DNA-Binding Proteins; D047908:Intracellular Signaling Peptides and Proteins; D007976:Leupeptins; D009687:Nuclear Proteins; D061988:Proteasome Inhibitors; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; C072553:benzyloxycarbonylleucyl-leucyl-leucine aldehyde