title: Role of the G-box element in regulation of chlorophyll biosynthesis in Arabidopsis roots.
abstract: Regulation of chlorophyll metabolism comprises strong transcriptional control together with a range of post-translational mechanisms during chloroplast biogenesis. Recently we reported that chlorophyll biosynthesis in Arabidopsis thaliana roots is regulated by auxin/cytokinin signaling via the combination of two transcription factors, LONG-HYPOCOTYL5 (HY5) and GOLDEN2-LIKE2 (GLK2). In this study, we examined the involvement of cis-elements in the expression of chlorophyll biosynthesis genes. Searches for predicted cis-elements in key chlorophyll biosynthesis genes and their co-expressed genes revealed coexistence of the G-box motif and the CCAATC motif, which may be targeted by HY5 and GLK factors, respectively, in their promoter regions. Deletion of the G-box from the promoter of the CHLH gene encoding the H subunit of Mg-chelatase resulted in the absence of its expression in roots but not in shoots, showing a differing involvement of the G-box in CHLH expression between shoots and roots. Our data suggest that transcription factors and cis-elements participating chlorophyll biosynthesis are substantially changed during organ differentiation, which may be linked to the differentiation of plastids.
authors: Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan. kkobayashi@bio.c.u-tokyo.ac.jp
authors: Koichi
authors: K
authors: Kobayashi
authors: Takeshi
authors: T
authors: Obayashi
authors: Tatsuru
authors: T
authors: Masuda
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism*; D001483:Base Sequence; D002734:Chlorophyll / Q000096:biosynthesis*; D018506:Gene Expression Regulation, Plant; D053263:Gene Regulatory Networks / Q000235:genetics; D017343:Genes, Plant / Q000235:genetics; D008969:Molecular Sequence Data; D059372:Nucleotide Motifs / Q000235:genetics; D010788:Photosynthesis / Q000235:genetics; D018517:Plant Roots / Q000235:genetics* / Q000378:metabolism*; D011401:Promoter Regions, Genetic
chemical_list: D002734:Chlorophyll