Chloroplast targeting of chloroplast division FtsZ2 proteins in Arabidopsis.
Plant nuclear genomes encode chloroplast division proteins homologous to the eubacterial cell division protein FtsZ. In higher plants, FtsZ genes constitute a small gene family that consists of two subgroups, FtsZ1 and FtsZ2. It was previously hypothesized that members of one family (FtsZ1) targeted chloroplasts, while members of the other family (FtsZ2) localized in the cytoplasm. We determined the full-length cDNA sequences of two FtsZ2 genes from Arabidopsis thaliana (AtFtsZ2-1 and AtFtsZ2-2) and found that the genes encode polypeptides of 478 and 473 amino acids, respectively, and both contain N-terminal extensions beyond what have previously been predicted. The N-terminal regions of both AtFtsZ2-1 and AtFtsZ2-2 were expressed as green fluorescent protein (GFP) fusions under the cauliflower mosaic virus 35S promoter in bombarded tobacco cells. Confocal laser scanning microscopy revealed both fusions exclusively localized to chloroplasts, demonstrating that the N-terminal regions function as chloroplast-targeting signals in vivo. Thus, FtsZ2 proteins function within chloroplasts.
Fujiwara
M
M
Plant Functions Laboratory, RIKEN, Hirosawa 2-1, Wako, Saitama 351-0198, Japan. mfuji@postman.riken.go.jp
Yoshida
S
S
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics*; D029681:Arabidopsis Proteins; D001483:Base Sequence; D002736:Chloroplasts / Q000235:genetics* / Q000378:metabolism; D018076:DNA, Complementary / Q000032:analysis; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D012315:RNA Caps / Q000235:genetics; D017386:Sequence Homology, Amino Acid
D029681:Arabidopsis Proteins; C436953:AtFtsZ2 protein, Arabidopsis; D018076:DNA, Complementary; C095113:FTSZ protein, Arabidopsis; D010940:Plant Proteins; D012315:RNA Caps