Identification of sequence elements regulating promoter activity and replication of a monopartite begomovirus-associated DNA {beta} satellite

• Published in: Journal of general virology 2009-01, Vol.90 (1), p.253-260
• Main Authors: Eini, Omid, Behjatnia, S. A. Akbar, Dogra, Satish, Dry, Ian B, Randles, John W, Rezaian, M. Ali
• Format: Article
• Language: English
• Subjects: Geminiviridae; Nicotiana tabacum
• ISSN: 0022-1317; 1465-2099
• DOI: 10.1099/vir.0.002980-0

1 School of Agriculture, Food and Wine, The University of Adelaide, Waite Campus, SA 5064, Australia 2 CSIRO Plant Industry, PO Box 350, Glen Osmond, SA 5064, Australia 3 Plant Protection Department, College of Agriculture, Zanjan University, Zanjan, Iran 4 Plant Protection Department, College of Agriculture, Shiraz University, Shiraz, Iran Correspondence John W. Randles john.randles{at}adelaide.edu.au DNA β is a circular single-stranded satellite DNA associated with certain monopartite begomoviruses (family Geminiviridae ) which causes economically important diseases such as cotton leaf curl disease. DNA β contains a single gene, βC1 , which encodes a pathogenicity protein responsible for symptom production. Transient expression studies in Nicotiana tabacum using the β -glucuronidase reporter gene driven by a βC1 promoter-deletion series of the DNA β associated with cotton leaf curl Multan virus identified a 68 nt region (between –139 and –207) which is important for βC1 transcription. This 68 nt region contains a G-box (CACGTG) located 143 nt upstream of the βC1 start codon. Mutation of the G-box resulted in a significant reduction in βC1 promoter activity and DNA β replication efficiency. In addition, the G-box motif was found to bind specifically to a protein(s) in nuclear extracts prepared from tobacco leaf tissues. Our results indicate that interaction of the G-box motif with host nuclear factors is important for efficient gene expression and replication of DNA β . A supplementary table of primer sequences is available with the online version of this paper.