Divergent fructokinase genes are differentially expressed in tomato.

AUTOR(ES)

Kanayama, Y

RESUMO

Two cDNA clones (Frk1 and Frk2) encoding fructokinase (EC 2.7.1.4) were isolated from tomato (Lycopersicon esculentum). The Frk2 cDNA encoded a deduced protein of 328 amino acids that was more than 90% identical with a previously characterized potato (Solanum tuberosum) fructokinase. In contrast, the Frk1 cDNA encoded a deduced protein of 347 amino acids that shared only 55% amino acid identity with Frk2. Both deduced proteins possessed and ATP-binding motif and putative substrate recognition site sequences identified in bacterial fructokinases. The Frk1 cDNA was expressed in a mutant yeast (Saccharomyces cerevisiae) line, which lacks the ability to phosphorylate glucose and fructose and is unable to grow on glucose or fructose. Mutant cells expressing Frk1 were complemented to grow on fructose but not glucose, indicating that Frk1 phosphorylates fructose but not glucose, and this activity was verified in extracts of transformed yeast. The mRNA corresponding to Frk2 accumulated to high levels in young, developing tomato fruit, whereas the Frk1 mRNA accumulated to higher levels late in fruit development. The results indicate that fructokinase in tomato is encoded by two divergent genes, which exhibit a differential pattern of expression during fruit development.

Documentos Relacionados

• The diageotropica mutation and synthetic auxins differentially affect the expression of auxin-regulated genes in tomato.
• Two divergent cellular src genes are expressed in Xenopus laevis.
• A Single Gene May Encode Differentially Localized Ca2+-ATPases in Tomato.
• Tumor promoter-inducible genes are differentially expressed in the developing mouse.
• Functional classes of bronchial mucosa genes that are differentially expressed in asthma