microRNA-mediated repression of rolled leaf1 specifies maize leaf polarity

Nature. 2004 Mar 4;428(6978):84-8. doi: 10.1038/nature02363.


In both animals and plants, many developmentally important regulatory genes have complementary microRNAs (miRNAs), which suggests that these miRNAs constitute a class of developmental signalling molecules. Leaves of higher plants exhibit a varying degree of asymmetry along the adaxial/abaxial (upper/lower) axis. This asymmetry is specified through the polarized expression of class III homeodomain/leucine zipper (HD-ZIPIII) genes. In Arabidopsis, three such genes, PHABULOSA (PHB), PHAVOLUTA (PHV) and REVOLUTA (REV), are expressed throughout the incipient leaf, but become adaxially localized after primordium emergence. Downregulation of the HD-ZIPIII genes allows expression of the KANADI and YABBY genes, which specify abaxial fate. PHB, PHV and REV transcripts contain a complementary site for miRNA165 and miRNA166, which can direct their cleavage in vitro. Here we show that miRNA166 constitutes a highly conserved polarizing signal whose expression pattern spatially defines the expression domain of the maize hd-zipIII family member rolled leaf1 (rld1). Moreover, the progressively expanding expression pattern of miRNA166 during leaf development and its accumulation in phloem suggests that miRNA166 may form a movable signal that emanates from a signalling centre below the incipient leaf.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Alleles
  • Amino Acid Sequence
  • Base Sequence
  • Body Patterning*
  • Down-Regulation
  • Gene Expression Regulation, Plant
  • Genes, Plant / genetics*
  • MicroRNAs / genetics
  • MicroRNAs / metabolism*
  • Molecular Sequence Data
  • Phenotype
  • Plant Leaves / embryology*
  • Plant Leaves / genetics
  • Plant Proteins / chemistry
  • Plant Proteins / genetics
  • Plant Proteins / metabolism
  • RNA Interference*
  • RNA, Plant / genetics
  • RNA, Plant / metabolism
  • Zea mays / embryology*
  • Zea mays / genetics*


  • MicroRNAs
  • Plant Proteins
  • RNA, Plant

Associated data

  • GENBANK/AY501430
  • GENBANK/AY501431
  • GENBANK/AY501432
  • GENBANK/AY501433
  • GENBANK/AY501434