Data mining the arabidopsis genome reveals fifteen 14-3-3 genes. Expression is demonstrated for two out of five novel genes

In plants, 14-3-3 proteins are key regulators of primary metabolism and mem brane transport. Although the current dogma states that 14-3-3 isoforms are not very specific with regard to target proteins, recent data suggest that the specificity may be high. Therefore, identification and characterizatio n of all 14-3-3 (GF14) isoforms in the model plant Arabidopsis are importan t. Using the information now available from The Arabidopsis Information Res ource, we found three new GF14 genes. The potential expression of these thr ee genes, and of two additional novel GF14 genes (Rosenquist et al., 2000), in leaves, roots, and flowers was examined using reverse transcriptase-pol ymerase chain reaction and cDNA library polymerase chain reaction screening . Under normal growth conditions, two of these genes were found to be trans cribed. These genes were named grf11 and grf12, and the corresponding new 1 4-3-3 isoforms were named GF14omicron and GF14iota, respectively. The gene coding for GF14omicron was expressed in leaves, roots, and flowers, whereas the gene coding for GF14iota was only expressed in flowers. Gene structure s and relationships between all members of the GF14 gene family were deduce d from data available through The Arabidopsis Information Resource. The dat a clearly support the theory that two 14-3-3 genes were present when eudico tyledons diverged from monocotyledons. In total, there are 15 14-3-3 genes (grfs 1-15) in Arabidopsis, of which 12 (grfs 1-12) now have been shown to be expressed.