Differential involvement of the IDRS cis-element in the developmental and environmental regulation of the AtFer1 ferritin gene from Arabidopsis.
Four different ferritin genes have been identified in Arabidopsis thaliana, namely AtFer1, 2, 3 and 4. AtFer1, which strongly accumulates in leaves treated with excess iron, contains in its promoter an Iron- Dependent Regulatory Sequence (IDRS). The IDRS sequence is responsible for repression of AtFer1 transcription under conditions of low iron supply. Arabidopsis plants transformed with a 1,400-bp AtFer1 promoter, with either a wild-type or a mutated IDRS fused to the beta-glucuronidase (GUS) reporter gene, enabled us to analyze the activity of the AtFer1 promoter in different tissues as well as during age-dependent or dark-induced senescence. Our results show that IDRS mediates AtFer1 expression during dark-induced senescence while it does not affect AtFer1 expression during age-dependent senescence or in young seedlings. Photoinhibition promoted either by high light or chilling temperature, or wounding, does not activate the AtFer1 promoter. In contrast, AtFer2, AtFer3, AtFer4 transcript abundances are increased in response to photoinhibition and AtFer3 transcript abundance is increased upon wounding. Taken together, our results indicate that other cis-elements, different from the IDRS, regulate the territory-specific or developmental expression of AtFer1 gene. Expression of this gene appears insensitive to some of the environmental stresses tested, which instead up-regulate other members of the Arabidopsis ferritin gene family.
Sezione di Fisiologia e Biochimica delle Piante, Dipartimento di Biologia, via Celoria 26, 20133 Milano, Italy.
Delia
D
Tarantino
Jean-Michel
JM
Petit
Stephane
S
Lobreaux
Jean-François
JF
Briat
Carlo
C
Soave
Irene
I
Murgia
D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D003080:Cold Temperature; D005293:Ferritins / Q000235:genetics* / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D005966:Glucuronidase / Q000235:genetics / Q000378:metabolism; D007501:Iron / Q000494:pharmacology; D008027:Light; D008969:Molecular Sequence Data; D018515:Plant Leaves / Q000235:genetics / Q000254:growth & development; D018517:Plant Roots / Q000235:genetics / Q000254:growth & development; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012045:Regulatory Sequences, Nucleic Acid / Q000235:genetics*; D013314:Stress, Mechanical; D013997:Time Factors
D029681:Arabidopsis Proteins; D011993:Recombinant Fusion Proteins; D005293:Ferritins; D007501:Iron; D005966:Glucuronidase