| Abstract Detail
Mechanisms of Gene Regulation Agarwal, Vikram [1], Ha, Misook [2], Chen, Z. Jeffrey [3]. The Role of Promoter Sequence Divergence in Nonadditive Gene Expression in Arabidopsis Allopolyploids. Polyploidy is a common phenomenon in many plants and some animals, and many crop species including wheat, cotton, and canola are polyploids. Polyploids are generated through multiplication of a single genome (autopolyploidy) or through combination of two or more divergent genomes (allopolyploidy). Arabidopsis allotetraploids can be resynthesized by hybridizing two related species, A. thaliana and A. arenosa. Microarray analysis indicated that expression of ~1500 genes in the allotetraploids is nonadditive (differed from the mean of parental expression values). The data suggest gene activation or silencing; however, the mechanisms responsible for nonadditivity, as well as the biological consequences, are poorly understood. One hypothesis is that regulatory sequences from two progenitors may diverge over time, and combining homoeologous (partially homologous) genes with different promoters and enhancers may contribute to gene expression variation. Here we report cloning and sequence analyses of promoter regions of twelve genes showing nonadditive expression patterns in the allotetraploids. Six of these genes are highly expressed in the A. thaliana parent and down-regulated in the allotetraploids, and the other six are highly expressed in A. arenosa and down-regulated in the allotetraploids. Genome-walking DNA libraries were constructed and used to amplify upstream regions of A. arenosa candidate genes. The amplicons were sequenced and aligned with their respective loci in A. thaliana. A high degree of promoter sequence divergence was detected between the two closely related species, including some large deletions in A. arenosa relative to A. thaliana. Comparative analysis of sequence motifs will allow us to address whether promoter sequence variation is correlated with expression variation in the resynthesized allopolyploids.
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Related Links:
The Chen Laboratory
1 - The University of Texas at Austin, Section of Molecular Cell and Developmental Biology, College of Natural Sciences, 1 University Station, A6700, Austin, TX, 78712, United States
2 - The University of Texas at Austin, Center for Computational Biology and Bioinformatics
3 - The University of Texas at Austin, Institute for Cellular and Molecular Biology
Keywords:
polyploidy
Arabidopsis.
Presentation Type: Plant Biology Abstract
Session: P
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM
Number: P36053
Abstract ID:2310 |
