title: GSBF1, a seedling-specific bZIP DNA-binding protein with preference for a 'split' G-box-related element in Brassica napus RbcS promoters.
abstract: Promoters of RbcS genes may contain a GS-box, which is a cis element with a core sequence related to the G-box, but split by a spacer of about 14 bp. Here we describe GSBF1, a DNA-binding protein that specifically interacts with a GS-box element located proximal to the G-box in the Brassica napus RbcS IV promoter. Sequence analysis of GSBF1 revealed a basic region/leucine zipper (bZIP) domain that displays structural features distinct from that of G-box binding factors (GBFs). Gel shift experiments showed that recombinant GSBF1 does not efficiently bind to the continuous G-box motif. RNA gel blot analysis indicated that GSBF1 transcripts are cotyledon-specific and accumulate to the highest levels during late seedling development in a ligh-dependent manner. During the same time period, RbcS IV transcript levels decreased simultaneously, suggesting that GSBF1 acts as a developmental, stage-specific, negative regulator of RbcS IV gene expression in rape seedlings.
authors.affiliation: University of Bochum, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Waldmüller
authors.forename: U
authors.initials: U
authors.lastname: Müller
authors.forename: G
authors.initials: G
authors.lastname: Link
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D001937:Brassica / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D018744:DNA, Plant / Q000235:genetics; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000235:genetics; D016350:Leucine Zippers; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics*; D012333:RNA, Messenger / Q000032:analysis; D018749:RNA, Plant / Q000032:analysis; D011993:Recombinant Fusion Proteins; D012273:Ribulose-Bisphosphate Carboxylase / Q000235:genetics*; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid
chemical_list: D018076:DNA, Complementary; D018744:DNA, Plant; D004268:DNA-Binding Proteins; C103242:GSBF1 protein, Brassica napus; D010940:Plant Proteins; D012333:RNA, Messenger; D018749:RNA, Plant; D011993:Recombinant Fusion Proteins; D012273:Ribulose-Bisphosphate Carboxylase