The R2R3-MYB gene family in plants

Table of all A. thaliana MYB genes

(a listing of all AtMYB genes with AGI genecode, synonyms, GenEMBL accessions, and gene-specific references)

MYB factors represent a family of proteins which include a conserved domain, the MYB DNA-binding domain. In contrast to animals, plants contain a MYB protein subfamily which is characterised by the R2R3-type MYB domain. The 'classical' MYB factors, which are related to c-Myb, seem to be involved in the control of the cell cycle in animals, plants and other higher eukaryotes. Systematic screens for knock-out mutations in MYB genes followed by phenotypic analyses, and the analysis of mutants with interesting phenotypes, have begun to unravel the functions of the 126 R2R3-MYB genes in Arabidopsis thaliana. R2R3-type MYB genes control many aspects of plant secondary metabolism, as well as the identity and fate of plant cells.

The first MYB gene identified was the 'oncogene' v-Myb from the avian MYeloBlastosis virus. This gene appears to have originated from a vertebrate gene by capture and subsequent modification. Many vertebrates contain three genes related to v-Myb (c-Myb, A-Myb and B-Myb), and other similar genes were identified in insects, plants, fungi and slime moulds. The encoded proteins are crucial to the control of proliferation and differentiation in a number of cell types and share the conserved MYB DNA-binding domain. This domain generally consists of up to three imperfect repeats, each forming a helix-turn-helix structure of about 53 amino acids. Characteristic of a MYB repeat are three regularly spaced tryptophan residues which form a tryptophan cluster in the three-dimensional helix-turn-helix structure. The three repeats from c-Myb are referred to as R1, R2 and R3. Repeats from other MYB proteins are categorized according to their similarity to either R1, R2 or R3.

(Text from COPB 4: 447-456; 2001)

super-imposition of two animal MYB DNA-binding domains

Some general references on MYB genes in plants

  • The R2R3-MYB gene family in Arabidopsis thaliana. R. Stracke, M. Werber, and B. Weisshaar
    Current Opinion in Plant Biology 4: 447-456 (2001)
  • c-MYB oncogene-like genes encoding three MYB repeats occur in all major plant lineages. H. Kranz, K. Scholz and B. Weisshaar
    The Plant Journal 21: 231-235 (2000)
  • Multifunctionality and diversity within the plant MYB-gene family. H. Jin and C. Martin
    Plant Molecular Biology 41: 577-585 (1999)
  • Function search in a large transcription factor family in Arabidopsis: assessing the potential of reverse genetics to identify insertion mutants in R2R3-MYB genes. R.C. Meissner, H. Jin, E. Cominelli, M. Denekamp, A. Fuertes, R. Greco, H.D. Kranz, S. Penfield, K. Petroni, A. Urzainqui, C. Martin, J. Paz-Ares, S. Smeekens, C. Tonelli, B. Weisshaar, E. Baumann, V. Klimyuk, S. Marillonnet, K. Patel, E. Speulman, A. Tissier, D. Bouchez, J. Jones, A. Pereira, E. Wisman, and M. Bevan
    The Plant Cell 11: 1827-1840 (1999)
  • Towards functional characterisation of the members of the R2R3-MYB gene family from Arabidopsis thaliana.H.D. Kranz, M. Denekamp, R. Greco, H.-L. Jin, A. Leyva, R. Meissner, K. Petroni, A. Urzainqui, M. Bevan, C. Martin, S. Smeekens, C. Tonelli, J. Paz-Ares, and B. Weisshaar
    The Plant Journal 16: 263-276 (1998)
  • More than 80 R2R3-MYB regulatory genes in the genome of Arabidopsis thaliana. I. Romero, A. Fuertes, M.J. Benito, J.M. Malpical, A. Leyva, and J. Paz-Ares
    The Plant Journal 14: 273-284 (1998)
  • MYB transcription factors in plants. C. Martin and J. Paz-Ares
    Trends in Genetics 13: 67-73 (1997)