Wu, Cheng-Chiang , Kramer, Elena M .
Gene Duplication and Functional Evolution of Floral Homeotic MADS-box Genes in Eudicots.
GENE duplication and subsequent diversification has long been thought to provide the raw material for the evolution of complex morphologies, including flowers, which are the key innovation of angiosperms. Currently the effect of post-duplication divergence on the evolution of protein interactions and biochemical functions is poorly understood. This aspect of functional evolution is especially critical for transcription factors, whose protein partners can influence DNA-binding specificity and selection of target genes and therefore, ultimately, morphology. Phylogenetic analyses suggest that coincident duplication events occurred in the APETALA1 (AP1), APETALA3 (AP3), AGAMOUS (AG), and SEPALLATA (SEP) lineages of MADS-box family transcription factors in close association with the emergence of the core eudicot angiosperm clade. This cluster of duplications is also correlated with frameshift events in the coding regions of the resultant AP1 and AP3 orthologous lineages, resulting in lineage-specific motifs at the C-terminal end that may influence the formation of higher order protein complexes. However, little is known about the expression patterns and protein interactions of these genes from taxa close to the duplication events. We have identified homologs of the AP1, AP3, AG, and SEP lineages, as well as the PISTILLATA (PI) lineage, from Meliosma dilleniifolia (Sabiaceae), which lies close to and before the duplication events, and Corylopsis sinensis (Hamamelidaceae), which arose soon after the duplications. The expression patterns of these genes will be studied in the two taxa using RT-PCR and in situ hybridization. We will also seek to employ quantitative in vivo biochemical approaches to study the protein-protein interactions of these genes and thereby potentially illuminate the evolution of higher order protein complex formation among floral MADS-box proteins. These studies will further our understanding of functional diversification of floral homeotic genes following gene duplication.
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1 - Harvard University, Department of Organismic and Evolutionary Biology, 16 Divinity Avenue, Biological Laboratories 1112, Cambridge, Massachusetts, 02138, USA
2 - Harvard Univerisity, Organismic and Evolutionary Biology, 16 Divinity Ave, Biolabs 1109, Cambridge, Massachusetts, 02138, USA
Presentation Type: Array
Location: Auditorium/Bell Memorial Union
Date: Tuesday, August 1st, 2006
Time: 12:30 PM