In vivo aggregation of maize Activator (Ac) transposase in nuclei of maize endosperm and Petunia protoplasts

Plant J. 1994 May;5(5):705-14. doi: 10.1111/j.1365-313x.1994.00705.x.


The transposase (TPase) of the maize transposon Activator (Ac) accumulates in the nuclei of maize endosperm and transfected Petunia protoplasts, where it aggregates into rod-like structures about 2 microm in length. In petunia protoplasts the amount of TPase aggregates increases with the strength of the promoter fused to the Ac-coding region. The excision frequency of a Ds element, however, does not increase proportionally. The data suggest that the aggregated TPase is not responsible for the mobilization of the Ds element, but rather is a transpositionally inactive form of the protein. In contrast to the full-length TPase, a functional, N-terminally truncated TPase derivative is inefficiently transported into the nucleus at high expression levels and aggregates predominantly in the cytoplasm. Accordingly, the N-terminus of the TPase is involved in nuclear localization and/or aggregation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Cell Nucleus / enzymology*
  • DNA-Binding Proteins / metabolism*
  • Molecular Sequence Data
  • Nucleotidyltransferases / metabolism*
  • Plants / enzymology*
  • Plants / genetics
  • Promoter Regions, Genetic
  • Protoplasts / enzymology*
  • Transfection
  • Transposases
  • Zea mays / enzymology*
  • Zea mays / genetics
  • Zea mays / ultrastructure


  • DNA-Binding Proteins
  • Nucleotidyltransferases
  • Transposases