Analysis of the Ac promoter: Structure and regulation

M. Fridlender, Y. Sitrit, O. Shaul, O. Gileadi, A. A. Levy

Research output: Contribution to journalArticlepeer-review

5 Scopus citations


The Ac-encoded transposase, a factor that is essential for the mobility of the Ac element, is expressed under the control of a promoter that lacks a conventional TATA box. The regulation of this promoter is poorly understood. We have analyzed Ac promoter structure and activity, both in vitro and in vivo, using transgenic tobacco plants and cell suspensions. A deletion analysis of the Ac 5' region showed that the minimal promoter is located within 70 bp of the major transcription initiation site (at position 334). The minimal promoter includes the sequence TAAGAAATA at position 294-303, i.e., about 30 nucleotides upstream from the transcription start site. This sequence binds specifically to the TATA-binding protein (TBP), suggesting that it is functional as a TATA box. The regulation of the Ac promoter was studied throughout plant development. Levels of Ac mRNA were low in all tissues studied, with higher expression being observed in dividing cells. In order to test whether Ac promoter is regulated during the cell cycle, a tobacco cell suspension transformed with Ac, was grown synchronously. No differences were found in Ac mRNA levels between cells in S, G2, M, or G1 phases; however, expression was lower in the stationary phase. We conclude that Ac promoter is not cell-cycle regulated but is expressed at a higher level in dividing cells. The possible relationship between promoter features and the regulation of Ac element transposition is discussed.

Original languageEnglish
Pages (from-to)306-314
Number of pages9
JournalMolecular and General Genetics
Issue number3
StatePublished - May 1998
Externally publishedYes

Bibliographical note

Funding Information:
Acknowledgements We wish to thank Dr. Gideon Grafi for help and discussions, Naomi Avivi, Tal Barchiahu and the greenhouse team for technical assistance; and Yigal Avivi for editing of the manuscript. We thank the Tobacco Science Research Laboratory, Japan Tobacco Inc., for permitting us to use the tobacco BY-2 cell suspension. This work was done with support grants from the Israeli Academy of Sciences to A. A. L. and O. G., and from BARD and Forchheimer to A. A. L. The experiments done in this work comply with the Israeli rules on biosafety.


  • Activator
  • Cell cycle
  • Promoter
  • TATA box
  • Transposon


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