Early elicitor induction in members of a novel multigene family coding forhighly related RING-H2 proteins in Arabidopsis thaliana

We describe the identification and structural characterization of a novel f amily of Arabidopsis genes related to ATL2 which encode a variant of the RI NG zinc finger domain, known as RING-H2. Analysis of genes selected by us a nd of sequences from Arabidopsis stored in databases permitted the predicti on of several RING-H2 proteins that contain highly homologous RING domains. The ATL gene family is represented by fifteen sequences that contain, in a ddition to the RING, a transmembrane domain which is located in most of the m towards the N-terminal end. Transgenic Arabidopsis seedlings carrying the ATL2 promoter fused to the GUS reporter gene revealed that the expression of ATL2 is rapidly induced after exposure to chitin or inactivated crude ce llulase preparations. Rapid induction of transcript accumulation of another member of the ATL family was also observed under the same conditions. Thes e results suggest that some ATLs may be involved in the early stages of the defense response triggered in plants in response to pathogen attack.