Submitted to: American Society of Plant Biologists Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 7/25/2002
Publication Date: 7/25/2003
Citation: Velten, J.P., Cazzonelli, C.I. 2003. Viral intergenic sequence repeats that fail to enhance gene expression in vivo. American Society of Plant Biologists Annual Meeting.
Technical Abstract: Viruses have relative small genomes that use compact, effective and occasionally overlapping regulatory elements for controlling gene expression and genome replication. The compact organization of many viral regulatory regions makes it easy to focus research on areas likely to contain control sequences, e.g. intergenic regions. However, the potential for element overlap and multiple function within those regions often makes interpretation of results difficult. In order to help clarify the structure-function relationship of plant viral intergenic regions, DNA sequence from these regions were scanned for small repeated sequence motifs, an approach based upon the assumption that repeated DNA sequences are often associated with transcriptional regulation. The identified small sequence elements were then fused to a minimal CaMV35S promoter-luciferase reporter gene and screened for their ability to enhance luciferase activity using an Agrobacterium-based, in vivo, transient assay. The ease of use and high sensitivity of the assay allowed efficient screening of a large number of potential enhancer elements within Agrobacterium-infused tobacco leaves. Several classes of repeated elements able to enhance gene activity were identified, and will be reported in an independent presentation. However, the majority had no significant affect on expression using this specific assay, a finding that can be just as significant to facilitating research in the field as the much smaller number of positive effectors. In this report we list sequence elements that failed to influence reporter gene expressions and discuss these results in the context of what is currently known regarding viral gene regulation.