title: Chlamydomonas NZF1, a tandem-repeated zinc finger factor involved in nitrate signalling by controlling the regulatory gene NIT2.
abstract: The Chlamydomonas reinhardtii NIT2 gene plays a central role in nitrate assimilation, thus, nit2 mutants are not able to sense or to use nitrate for growth. NIT2 protein is an RWP-RK-type transcriptional factor related to nodule inception (Nin, NLP) proteins from plants. NIT2 expression is down-regulated in ammonium and up-regulated under nitrogen deprivation. However, intracellular nitrate is required to activate NIT2 for subsequent expression of NIA1 and other nitrate assimilation genes. In this work, mutants defective in nitrate sensing have been studied. The identification of genomic regions affected allows proposing putative loci/genes for nitrate signalling in the alga. Among them, a CrNZF1 (Nitrate Zinc Finger 1) that encodes a tandem zinc finger protein CCCH-type. In the nzf1 mutant, the expression of the regulatory gene NIT2 is decreased and also that of nitrate assimilation genes. In this mutant, polyadenylated forms of NIT2 with different lengths could be detected, whereas in the wild type there appeared preferentially the longest forms. CrNZF1 is proposed to regulate NIT2 polyadenylation and thus nitrate signalling and nitrate-dependent growth in the alga.
authors.affiliation: Departamento de Bioquimica y Biologia Molecular, Facultad de Ciencias, Universidad de Cordoba, Campus de Rabanales, Campus de Excelencia Internacional Agroalimentario (CeiA3), Edif. Severo Ochoa, 14071, Córdoba, Spain.
authors.forename: Jose Javier
authors.initials: JJ
authors.lastname: Higuera
authors.forename: Emilio
authors.initials: E
authors.lastname: Fernandez
authors.forename: Aurora
authors.initials: A
authors.lastname: Galvan
mesh_terms: D000595:Amino Acid Sequence; D002696:Chlamydomonas / Q000235:genetics*; D018506:Gene Expression Regulation, Plant; D005809:Genes, Regulator; D005816:Genetic Complementation Test; D018745:Genome, Plant / Q000235:genetics; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D009566:Nitrates / Q000378:metabolism*; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D026723:Polyadenylation; D011401:Promoter Regions, Genetic / Q000235:genetics; D020449:Repetitive Sequences, Amino Acid; D015398:Signal Transduction / Q000235:genetics; D014170:Transformation, Genetic; D016335:Zinc Fingers
chemical_list: D009566:Nitrates; D010940:Plant Proteins
keywords: nitrate assimilation