title: A C2H2 zinc finger protein FEMU2 is required for fox1 expression in Chlamydomonas reinhardtii.
abstract: Chlamydomonas reinhardtii fox1 gene encodes a ferroxidase that is involved in cellular Fe uptake and highly induced during Fe deficient conditions. In an effort to identify fox1 promoter regulatory elements, an insertional library was generated in a transgenic Chlamydomonas strain (2A38) harboring an arylsulfatase (ARS) reporter gene driven by the fox1 promoter. Mutants with a defective response to low iron conditions were selected for further study. Among these, a strain containing a disrupted femu2 gene was identified. Activation of the fox1 promoter by the femu2 gene product was confirmed by silencing the femu2 gene using RNA interference. In three femu2 RNAi transgenic lines (IR3, IR6, and IR7), ARS reporter gene activities declined by 84.3%, 86.4%, and 88.8%, respectively under Fe deficient conditions. Furthermore, RT-PCR analysis of both the femu2 mutant and the RNAi transgenic lines showed significantly decreased transcript abundance of the endogenous fox1 gene under Fe deficient conditions. Amino acid sequence analysis of the femu2 gene product identified three potential C2H2 zinc finger (ZF) motifs and a nuclear localization study suggests that FEMU2 is localized to the nucleus. In addition, a potential FEMU2 binding site ((G/T)TTGG(G/T)(G/T)T) was identified using PCR-mediated random binding site selection. Taken together, this evidence suggests that FEMU2 is involved in up-regulation of the fox1 gene in Fe deficient cells.
authors.affiliation: Key Laboratory of Biology and Genetic Resources of Tropical Crops, Ministry of Agriculture, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Science, Haikou, 571101, China.
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Deng
authors.affiliation: Key Laboratory of Biology and Genetic Resources of Tropical Crops, Ministry of Agriculture, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Science, Haikou, 571101, China.
authors.forename: Jinghao
authors.initials: J
authors.lastname: Yang
authors.affiliation: Key Laboratory of Biology and Genetic Resources of Tropical Crops, Ministry of Agriculture, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Science, Haikou, 571101, China.
authors.forename: Xiaoxia
authors.initials: X
authors.lastname: Wu
authors.affiliation: Key Laboratory of Biology and Genetic Resources of Tropical Crops, Ministry of Agriculture, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Science, Haikou, 571101, China.
authors.forename: YaJun
authors.initials: Y
authors.lastname: Li
authors.affiliation: School of Science, Hainan Medical College, Haikou, 571101, China.
authors.forename: Xiaowen
authors.initials: X
authors.lastname: Fei
mesh_terms: D000595:Amino Acid Sequence; D001192:Arylsulfatases / Q000378:metabolism; D001483:Base Sequence; D001665:Binding Sites; D002570:Ceruloplasmin / Q000235:genetics*; D016825:Chlamydomonas reinhardtii / Q000235:genetics* / Q000378:metabolism*; D017124:Conserved Sequence; D004789:Enzyme Activation; D018506:Gene Expression Regulation, Plant; D020868:Gene Silencing; D042541:Intracellular Space; D007501:Iron / Q000378:metabolism; D000090463:Iron Deficiencies; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D011485:Protein Binding; D054730:Protein Interaction Domains and Motifs; D021381:Protein Transport; D016415:Sequence Alignment; D016335:Zinc Fingers / Q000235:genetics
chemical_list: D010940:Plant Proteins; D007501:Iron; D002570:Ceruloplasmin; D001192:Arylsulfatases