Cytoskeleton Structure and Dynamics
Kandasamy, Muthugapatti K. , Burgos-Rivera, Brunilis , McKinney, Elizabeth, C. , Ruzicka, Daniel, R. , Meagher, Richard, B. .
Class-specific interaction of profilin and ADF isovariants with actin in the regulation of plant development.
Two ancient and highly divergent actin-based cytoskeletal systems appear to have evolved in higher plants. Plant genomes encode complex actin and actin-binding protein (ABP) gene families and most are phylogenetically grouped into gene classes with distinct vegetative or constitutive and reproductive expression patterns. In Arabidopsis, ectopic expression of high levels of a reproductive class actin, ACT1, in vegetative tissues caused severe dwarfing of plants with aberrant organization of most plant organs and cell types due to severely altered actin cytoskeletal architecture. On the other hand, overexpression of a vegetative class actin, ACT2 produces insignificant phenotypic changes. We proposed that the misexpression of the pollen-specific ACT1 in vegetative cell types affects the dynamics of actin due to its poor interaction with endogenous vegetative ABPs. In order to examine the functionally distinct interactions among the major classes of actins and ABPs, we ectopically co-expressed reproductive profilin (PRF4) or actin-depolymerizing factor (ADF) isovariants (e.g. ADF7) with ACT1. Our results demonstrated that the co-expression of these reproductive, but not vegetative, ABP isovariants suppressed the ectopic ACT1 expression phenotypes and restored wild-type stature and normal actin cytoskeletal architecture to the double transgenic plants. Thus, the actins and ABPs have evolved class-specific protein-protein interactions in vivo, which are essential to the normal regulation of plant growth and development.
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1 - University of Georgia, Genetics, Life Sciences Building, Athens, GA, 30602, USA
2 - University of Georgia, Genetics
actin depolymerizing factor
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM