Poster: Organelle Biogenesis
Abs #
1154: Analysis of Intracellular Localization of the PEND Protein.
PEND protein is a DNA-binding protein in the plastid envelope membrane originally discovered in pea. A DNA-binding domain called cbZIP is present at the N-terminus. A putative protein (ATF4F15.280) in the Arabidopsis thaliana chromosome 3 and the GSBF1 (GI:2306408A) protein of Brassica napus were found to be PEND homologues. We isolated additional PEND homologues from Brassica napus, Prunus yedoensis and Cucumis sativus. In addition, tomato and wheat cDNAs encoding PEND homologues were found. PEND protein is therefore present widely in angiosperms. The cbZIP and the C-terminal membrane spanning regions are highly conserved. Full length PEND-GFP fusion protein was localized to the chloroplasts. The constructs without the N-terminus 15 amino acids was targeted to the nucleus. This was confirmed by immunoblot analysis. We will also report on the results with stabley transformed plants. The cbZIP-GFP fusion protein was localized in the chloroplasts and also targeted to the nucleus in 50 of transformed cells in a transient expression system. Essentially similar results were obtained for A. thaliana and B. napus homologues. Furthermore, in the stably transformated plants, PEND protein was localized almost only in the chloroplasts. Our current hypothesis is that, although the PEND protein is primarily localized in the chloroplast envelope, a damage to the chloroplast might trigger relocalization of the processed PEND protein to the nucleus.
