Plant stress proteins of the thaumatin-like family discovered in animals.
Thaumatin-like proteins (TLPs) are polypeptides of about 200 residues synthesized by plants in response to fungal infection. In addition to the exceptionally strong sweet taste exhibited by some members, they are also reported to be endowed with endo-beta-1,3-glucanase activity and alpha-amylase inhibiting properties. However, the detailed mechanism of their antifungal action is not completely understood. So far, TLPs have only been described in plants, with several members of the family expressed in the same species. Here, for the first time in animals, we report the identification of two genes encoding members of the thaumatin-like proteins family in the desert locust Schistocerca gregaria and show their expression in different parts of the body. Southern blot and Western blot experiments revealed the presence of orthologous genes and their expression products in the related species Locusta migratoria. A search through the available genomes yielded similar sequences in the nematode Caenorhabditis but not in Drosophila and other insects. A three-dimensional model of S. gregaria TLP suggests a glucanase function. As in plants, TLPs could play a defense role in insects against pathogens.
Dipartimento di Chimica e Biotecnologie Agrarie, University of Pisa, via S. Michele, 4, 56124 Pisa, Italy.
Anna
A
Brandazza
Sergio
S
Angeli
Mariella
M
Tegoni
Christian
C
Cambillau
Paolo
P
Pelosi
D000595:Amino Acid Sequence; D000818:Animals; D002107:Caenorhabditis; D003001:Cloning, Molecular; D004330:Drosophila; D006110:Grasshoppers; D006360:Heat-Shock Proteins / Q000032:analysis* / Q000737:chemistry / Q000235:genetics; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000032:analysis* / Q000737:chemistry / Q000235:genetics; D016133:Polymerase Chain Reaction; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000737:chemistry; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014026:Nicotiana / Q000737:chemistry
D006360:Heat-Shock Proteins; D010940:Plant Proteins; D011994:Recombinant Proteins; C003427:thaumatin protein, plant