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Genetics Section

Kim, Sangtae [2], Soltis, Pamela S. [1], Soltis, Douglas E. [2].

Duplication of the AP2 domain preceded the split of the major lineages of the APETALA2-like gene family.

The combined processes of gene duplication, nucleotide substitution, domain duplication, and intron/exon shuffling can generate a complex set of related genes that may differ substantially in their expression patterns and functions. The APETALA2-like (AP2-like) gene family exhibits patterns of both gene and domain duplication, coupled with changes in sequence, exon arrangement, and expression. These genes perform an array of functions including the establishment of the floral meristem, the specification of floral organ identity, the regulation of floral homeotic gene expression, the regulation of ovule development, and the growth of floral organs in angiosperms. To determine patterns of gene diversification and shifts in expression, we conducted a series of phylogenetic analyses. These studies of AP2-like genes indicate that the AP2 domain was duplicated prior to the divergence of the two major lineages of AP2-like genes, euAP2 and ANT. Structural features of the AP2-like genes, as well as phylogenetic analyses of nucleotide and amino acid sequences of the AP2-like gene family, support the presence of the two major lineages. The ANT lineage is supported by an 11-aa insertion in the AP2-R1 domain and a one-aa insertion in the AP2-R2 domain, relative to all other members of the AP2-like family. Conversely, microRNA172 (miR172) binding sequences, the function of which was studied in some of the AP2-like genes in Arabidopsis, are restricted to the euAP2 lineage. Within the ANT lineage, the euANT lineage is characterized by three conserved motifs (euANT1, euANT2, and euANT3) in the pre-domain region. Basal sequences of the ANT lineage share short (44-81 aa) pre-domain sequences compared to the longer pre-domain sequences of the euANT lineage (127-307 aa). Our expression studies showed that the euAP2 homologue from Amborella trichopoda, the sister to all other angiosperms, was expressed in all floral organs as well as leaves.

1 - University of Florida, Department of Natural History, Florida Museum of Natural History, P.O. Box 117800, Gainesville, Florida, 32611-7800, USA
2 - University of Florida, Department of Botany, 220 Bartram Hall, P.O. Box 118526, Gainesville, Florida, 32611-8526, USA

ANT lineage
ANT motif
euANT motif
euAP2 lineage

Presentation Type: Paper
Session: 53-10
Location: Peruvian (Cliff Lodge)
Date: Wednesday, August 4th, 2004
Time: 3:30 PM
Abstract ID:133

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