FILAMENTOUS FLOWER, a meristem and organ identity gene of Arabidopsis, encodes a protein with a zinc finger and HMG-related domains

  1. Shinichiro Sawa,
  2. Keiro Watanabe,
  3. Koji Goto,
  4. Eiko Kanaya,
  5. Eugene Hayato Morita, and
  6. Kiyotaka Okada
  1. Department of Botany, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan; Institute for Chemical Research, Kyoto University, Uji, Kyoto, 611-0011, Japan; Biomolecular Engineering Research Institute, Suita, Osaka, 565-0874, Japan; Department of Chemistry, Faculty of Science, Ehime University, Matsuyama, Ehime 790-8577, Japan

Abstract

Distinctive from that of the animal system, the basic plan of the plant body is the continuous formation of a structural unit, composed of a stem with a meristem at the top and lateral organs continuously forming at the meristem. Therefore, mechanisms controlling the formation, maintenance, and development of a meristem will be a key to understanding the body plan of higher plants. Genetic analyses offilamentous flower (fil) mutants have indicated thatFIL is required for the maintenance and growth of inflorescence and floral meristems, and of floral organs of Arabidopsis thaliana. FIL encodes a protein carrying a zinc finger and a HMG box-like domain, which is known to work as a transcription regulator. As expected, the FIL protein was shown to have a nuclear location. In situ hybridization clearly demonstrated that FIL is expressed only at the abaxial side of primordia of leaves and floral organs. Transgenic plants, ectopically expressing FIL, formed filament-like leaves with randomly arranged cells at the leaf margin. Our results indicate that cells at the abaxial side of the lateral organs are responsible for the normal development of the organs as well as for maintaining the activity of meristems.

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Footnotes

  • Corresponding author.

  • E-MAIL kiyo{at}ok-lab.bot.kyoto-u.ac.jp; FAX 81-75-753-4257.

    • Received January 29, 1999.
    • Accepted March 2, 1999.
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