Sequence and expression differences underlie functional specialization of Arabidopsis microRNAs miR159 and miR319

Dev Cell. 2007 Jul;13(1):115-25. doi: 10.1016/j.devcel.2007.04.012.


Many microRNAs (miRNAs) are encoded by small gene families. In a third of all conserved Arabidopsis miRNA families, members vary at two or more nucleotide positions. We have focused on the related miR159 and miR319 families, which share sequence identity at 17 of 21 nucleotides, yet affect different developmental processes through distinct targets. MiR159 regulates MYB mRNAs, while miR319 predominantly acts on TCP mRNAs. In the case of miR319, MYB targeting plays at most a minor role because miR319 expression levels and domain limit its ability to affect MYB mRNAs. In contrast, in the case of miR159, the miRNA sequence prevents effective TCP targeting. We complement these observations by identifying nucleotide positions relevant for miRNA activity with mutants recovered from a suppressor screen. Together, our findings reveal that functional specialization of miR159 and miR319 is achieved through both expression and sequence differences.

Publication types

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

MeSH terms

  • Arabidopsis / genetics*
  • Arabidopsis / growth & development
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism
  • Base Sequence
  • Gene Expression Regulation, Developmental*
  • Gene Expression Regulation, Plant*
  • MicroRNAs / genetics*
  • Point Mutation
  • RNA, Plant / genetics
  • Transcription Factors / genetics
  • Transcription Factors / metabolism


  • Arabidopsis Proteins
  • MicroRNAs
  • Myb protein, Arabidopsis
  • RNA, Plant
  • Transcription Factors