Logo of plntcellLink to Publisher's site
Plant Cell. 1999 Nov; 11(11): 2139–2152.
PMCID: PMC144121

IFL1, a gene regulating interfascicular fiber differentiation in Arabidopsis, encodes a homeodomain-leucine zipper protein.


Arabidopsis inflorescence stems develop extraxylary fibers at specific sites in interfascicular regions. The spatial specification of interfascicular fiber differentiation is regulated by the INTERFASCICULAR FIBERLESS1 (IFL1) gene because mutation of that gene abolishes the formation of normal interfascicular fibers in Arabidopsis stems. To understand further the role of IFL1 in the specification of fiber differentiation, we cloned the IFL1 gene by using a positional cloning strategy. Sequence analysis showed that the IFL1 gene encodes a transcription factor that has the same features as a family of homeodomain-leucine zipper (HD-ZIP) proteins found only in plants. The predicted IFL1 protein is composed of three distinct domains, including a 60-amino acid HD at the N terminus followed by a 28-amino acid ZIP motif and a 724-amino acid C-terminal region. A nuclear targeting assay showed that IFL1 is able to direct a beta-glucuronidase fusion protein into the nucleus, which is consistent with IFL1's presumed function as a transcription factor. Gene expression analysis demonstrated that the IFL1 gene is expressed in the interfascicular regions in which fibers differentiate, which is consistent with its role in the control of interfascicular fiber differentiation. Furthermore, the IFL1 gene was shown to be expressed in the vascular regions, indicating its possible role in the regulation of vascular tissue formation. This possibility is supported by the observation that differentiation of both xylary fibers and vessel elements is altered in the vascular bundles of ifl1 mutants. Our results provide direct evidence that an HD-ZIP protein plays a role in the spatial control of fiber differentiation.

Full Text

The Full Text of this article is available as a PDF (749K).

Selected References

These references are in PubMed. This may not be the complete list of references from this article.
  • Affolter M, Schier A, Gehring WJ. Homeodomain proteins and the regulation of gene expression. Curr Opin Cell Biol. 1990 Jun;2(3):485–495. [PubMed]
  • Aloni R. Role of auxin and gibberellin in differentiation of primary Phloem fibers. Plant Physiol. 1979 Apr;63(4):609–614. [PMC free article] [PubMed]
  • Aloni R. Role of cytokinin in differentiation of secondary xylem fibers. Plant Physiol. 1982 Dec;70(6):1631–1633. [PMC free article] [PubMed]
  • Aoyama T, Dong CH, Wu Y, Carabelli M, Sessa G, Ruberti I, Morelli G, Chua NH. Ectopic expression of the Arabidopsis transcriptional activator Athb-1 alters leaf cell fate in tobacco. Plant Cell. 1995 Nov;7(11):1773–1785. [PMC free article] [PubMed]
  • Baima S, Nobili F, Sessa G, Lucchetti S, Ruberti I, Morelli G. The expression of the Athb-8 homeobox gene is restricted to provascular cells in Arabidopsis thaliana. Development. 1995 Dec;121(12):4171–4182. [PubMed]
  • Bent AF, Kunkel BN, Dahlbeck D, Brown KL, Schmidt R, Giraudat J, Leung J, Staskawicz BJ. RPS2 of Arabidopsis thaliana: a leucine-rich repeat class of plant disease resistance genes. Science. 1994 Sep 23;265(5180):1856–1860. [PubMed]
  • Fukuda Hiroo. XYLOGENESIS: INITIATION, PROGRESSION, AND CELL DEATH. Annu Rev Plant Physiol Plant Mol Biol. 1996 Jun;47(NaN):299–325. [PubMed]
  • Gälweiler L, Guan C, Müller A, Wisman E, Mendgen K, Yephremov A, Palme K. Regulation of polar auxin transport by AtPIN1 in Arabidopsis vascular tissue. Science. 1998 Dec 18;282(5397):2226–2230. [PubMed]
  • Gehring WJ, Müller M, Affolter M, Percival-Smith A, Billeter M, Qian YQ, Otting G, Wüthrich K. The structure of the homeodomain and its functional implications. Trends Genet. 1990 Oct;6(10):323–329. [PubMed]
  • Graba Y, Aragnol D, Pradel J. Drosophila Hox complex downstream targets and the function of homeotic genes. Bioessays. 1997 May;19(5):379–388. [PubMed]
  • Hardtke CS, Berleth T. The Arabidopsis gene MONOPTEROS encodes a transcription factor mediating embryo axis formation and vascular development. EMBO J. 1998 Mar 2;17(5):1405–1411. [PMC free article] [PubMed]
  • Jefferson RA, Kavanagh TA, Bevan MW. GUS fusions: beta-glucuronidase as a sensitive and versatile gene fusion marker in higher plants. EMBO J. 1987 Dec 20;6(13):3901–3907. [PMC free article] [PubMed]
  • Kerstetter RA, Hake S. Shoot Meristem Formation in Vegetative Development. Plant Cell. 1997 Jul;9(7):1001–1010. [PMC free article] [PubMed]
  • Konieczny A, Ausubel FM. A procedure for mapping Arabidopsis mutations using co-dominant ecotype-specific PCR-based markers. Plant J. 1993 Aug;4(2):403–410. [PubMed]
  • Larkin JC, Marks MD, Nadeau J, Sack F. Epidermal cell fate and patterning in leaves. Plant Cell. 1997 Jul;9(7):1109–1120. [PMC free article] [PubMed]
  • Lu P, Porat R, Nadeau JA, O'Neill SD. Identification of a meristem L1 layer-specific gene in Arabidopsis that is expressed during embryonic pattern formation and defines a new class of homeobox genes. Plant Cell. 1996 Dec;8(12):2155–2168. [PMC free article] [PubMed]
  • Masucci JD, Rerie WG, Foreman DR, Zhang M, Galway ME, Marks MD, Schiefelbein JW. The homeobox gene GLABRA2 is required for position-dependent cell differentiation in the root epidermis of Arabidopsis thaliana. Development. 1996 Apr;122(4):1253–1260. [PubMed]
  • Meijer AH, Scarpella E, van Dijk EL, Qin L, Taal AJ, Rueb S, Harrington SE, McCouch SR, Schilperoort RA, Hoge JH. Transcriptional repression by Oshox1, a novel homeodomain leucine zipper protein from rice. Plant J. 1997 Feb;11(2):263–276. [PubMed]
  • Qian YQ, Billeter M, Otting G, Müller M, Gehring WJ, Wüthrich K. The structure of the Antennapedia homeodomain determined by NMR spectroscopy in solution: comparison with prokaryotic repressors. Cell. 1989 Nov 3;59(3):573–580. [PubMed]
  • Reiser L, Modrusan Z, Margossian L, Samach A, Ohad N, Haughn GW, Fischer RL. The BELL1 gene encodes a homeodomain protein involved in pattern formation in the Arabidopsis ovule primordium. Cell. 1995 Dec 1;83(5):735–742. [PubMed]
  • Rerie WG, Feldmann KA, Marks MD. The GLABRA2 gene encodes a homeo domain protein required for normal trichome development in Arabidopsis. Genes Dev. 1994 Jun 15;8(12):1388–1399. [PubMed]
  • Ruberti I, Sessa G, Lucchetti S, Morelli G. A novel class of plant proteins containing a homeodomain with a closely linked leucine zipper motif. EMBO J. 1991 Jul;10(7):1787–1791. [PMC free article] [PubMed]
  • Schena M, Davis RW. HD-Zip proteins: members of an Arabidopsis homeodomain protein superfamily. Proc Natl Acad Sci U S A. 1992 May 1;89(9):3894–3898. [PMC free article] [PubMed]
  • Schena M, Davis RW. Structure of homeobox-leucine zipper genes suggests a model for the evolution of gene families. Proc Natl Acad Sci U S A. 1994 Aug 30;91(18):8393–8397. [PMC free article] [PubMed]
  • Schena M, Lloyd AM, Davis RW. The HAT4 gene of Arabidopsis encodes a developmental regulator. Genes Dev. 1993 Mar;7(3):367–379. [PubMed]
  • Schiefelbein JW, Masucci JD, Wang H. Building a root: the control of patterning and morphogenesis during root development. Plant Cell. 1997 Jul;9(7):1089–1098. [PMC free article] [PubMed]
  • Schindler U, Beckmann H, Cashmore AR. HAT3.1, a novel Arabidopsis homeodomain protein containing a conserved cysteine-rich region. Plant J. 1993 Jul;4(1):137–150. [PubMed]
  • Schmidt R, Love K, West J, Lenehan Z, Dean C. Description of 31 YAC contigs spanning the majority of Arabidopsis thaliana chromosome 5. Plant J. 1997 Mar;11(3):563–572. [PubMed]
  • Sessa G, Morelli G, Ruberti I. The Athb-1 and -2 HD-Zip domains homodimerize forming complexes of different DNA binding specificities. EMBO J. 1993 Sep;12(9):3507–3517. [PMC free article] [PubMed]
  • Sessa G, Steindler C, Morelli G, Ruberti I. The Arabidopsis Athb-8, -9 and -14 genes are members of a small gene family coding for highly related HD-ZIP proteins. Plant Mol Biol. 1998 Nov 1;38(4):609–622. [PubMed]
  • Szymanski DB, Marks MD. GLABROUS1 overexpression and TRIPTYCHON alter the cell cycle and trichome cell fate in Arabidopsis. Plant Cell. 1998 Dec;10(12):2047–2062. [PMC free article] [PubMed]
  • Varagona MJ, Schmidt RJ, Raikhel NV. Nuclear localization signal(s) required for nuclear targeting of the maize regulatory protein Opaque-2. Plant Cell. 1992 Oct;4(10):1213–1227. [PMC free article] [PubMed]
  • Vollbrecht E, Veit B, Sinha N, Hake S. The developmental gene Knotted-1 is a member of a maize homeobox gene family. Nature. 1991 Mar 21;350(6315):241–243. [PubMed]
  • Ye ZH, Varner JE. Gene expression patterns associated with in vitro tracheary element formation in isolated single mesophyll cells of Zinnia elegans. Plant Physiol. 1993 Nov;103(3):805–813. [PMC free article] [PubMed]
  • Zhong R, Taylor JJ, Ye ZH. Disruption of interfascicular fiber differentiation in an Arabidopsis mutant. Plant Cell. 1997 Dec;9(12):2159–2170. [PMC free article] [PubMed]

Articles from The Plant Cell are provided here courtesy of American Society of Plant Biologists


Save items

Related citations in PubMed

See reviews...See all...

Cited by other articles in PMC

See all...


  • Gene
    Gene records that cite the current articles. Citations in Gene are added manually by NCBI or imported from outside public resources.
  • Gene (nucleotide)
    Gene (nucleotide)
    Records in Gene identified from shared sequence and PMC links.
  • GEO Profiles
    GEO Profiles
    Gene Expression Omnibus (GEO) Profiles of molecular abundance data. The current articles are references on the Gene record associated with the GEO profile.
  • HomoloGene
    HomoloGene clusters of homologous genes and sequences that cite the current articles. These are references on the Gene and sequence records in the HomoloGene entry.
  • MedGen
    Related information in MedGen
  • Nucleotide
    Primary database (GenBank) nucleotide records reported in the current articles as well as Reference Sequences (RefSeqs) that include the articles as references.
  • Pathways + GO
    Pathways + GO
    Pathways and biological systems (BioSystems) that cite the current articles. Citations are from the BioSystems source databases (KEGG and BioCyc).
  • Protein
    Protein translation features of primary database (GenBank) nucleotide records reported in the current articles as well as Reference Sequences (RefSeqs) that include the articles as references.
  • PubMed
    PubMed citations for these articles

Recent Activity

Your browsing activity is empty.

Activity recording is turned off.

Turn recording back on

See more...