Molecular evolution of the AP2 subfamily.
The AP2 (APETALA2)/EREBP (Ethylene Responsive Element Binding Protein) multigene family includes developmentally and physiologically important transcription factors. AP2/EREBP genes are divided into two subfamilies: AP2 genes with two AP2 domains and EREBP genes with a single AP2/ERF (Ethylene Responsive Element Binding Factor) domain. Based on previous phylogenetic analyses, AP2 genes can be divided into two clades, AP2 and ANT groups. To clarify the molecular evolution of the AP2 subfamily, we isolated and sequenced genes with two AP2 domains from three gymnosperms, Cycas revoluta, Ginkgo biloba, and Gnetum parvifolium,as well as from the moss Physcomitrella patens. Expressions of AP2-like genes, including AP2, in Arabidopsis thaliana are regulated by the microRNA miR172. We found that the target site of miR172 is significantly conserved in gymnosperm AP2 homologs, suggesting that regulatory mechanisms of gene expression using microRNA have been conserved over the three hundred million years since the divergence of gymnosperm and flowering plant lineages. We inferred a phylogenetic relationship of these genes with the green alga Chlamydomonas reinhardtii and seed-plant genes available in public DNA databases. The phylogenetic tree showed that the AP2 subfamily diverged into the AP2 and ANT groups before the last common ancestor of land plants and after C. reinhardtii diverged from the land-plant lineage. The tree also indicated that each AP2 and ANT group further diverged into several clades through gene duplications prior to the divergence of gymnosperms and angiosperms.
Shigyo
Mikao
M
Department of General System Studies, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Tokyo 153-8902, Japan.
Hasebe
Mitsuyasu
M
Ito
Motomi
M
D000818:Animals; D029681:Arabidopsis Proteins; D016825:Chlamydomonas reinhardtii / Q000235:genetics; D032462:Cycadopsida / Q000235:genetics*; D019143:Evolution, Molecular; D020440:Gene Duplication; D018506:Gene Expression Regulation, Plant / Q000235:genetics*; D018398:Homeodomain Proteins / Q000235:genetics*; D019684:Magnoliopsida / Q000235:genetics; D035683:MicroRNAs / Q000235:genetics; D005810:Multigene Family / Q000235:genetics*; D009687:Nuclear Proteins; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics*; D017434:Protein Structure, Tertiary / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics*
C499534:APETALA2 protein, Arabidopsis; D029681:Arabidopsis Proteins; D018398:Homeodomain Proteins; D035683:MicroRNAs; D009687:Nuclear Proteins; D010940:Plant Proteins; D014157:Transcription Factors