From Genome to Life:

HEDDAD Mounia

University, Biochemistry And Biophysics, Arrhenius Laboratories For Natural Sciences, Stockholm 106 90, Sweden

title: The expression and localisation studies of the stress induced and stress enhanced proteins in Arabidopsis thaliana.

The investigation of stress proteins localised in the chloroplast of Arabidopsis thaliana ended in the identification and cloning of five new proteins belonging to the extended family of the light harvesting chlorophyll a/b binding proteins (CAB). Two of these proteins belong to the ELIP (early light-inducible proteins) family. The transcripts of ELIPs were transiently expressed under high light conditions, and the encoded proteins were harbouring a typical structure of three transmembrane helices. The three other proteins were included into a new family, designated stress-enhanced protein (SEP). This appellation is due to a four to ten fold increase in the transcript levels under light stress conditions. The predicted structures of the SEPs differed from those of ELIPs and CAB proteins; they were found composed of two transmembrane helices. The expression studies at the protein level revealed a perfect correlation between the transcription and the translation of these proteins. The preliminary results from the localisation studies indicate a close location of ELIP1, ELIP2 and SEP2 to the light harvesting complex II of the photosystem II.