Transposition of the Autonomous Fot1 Element in the Filamentous Fungus Fusarium oxysporum

Corresponding author: Marie-Josée Daboussi, Institut de Génétique et Microbiologie, Université Paris-sud, Bâtiment 400, 91405 Orsay Cedex, France., daboussi{at}igmors.u-psud.fr (E-mail)

Communicating editor: M. J. SIMMONS

Autonomous mobility of different copies of the Fot1 element was determined for several strains of the fungal plant pathogen Fusarium oxysporum to develop a transposon tagging system. Two Fot1 copies inserted into the third intron of the nitrate reductase structural gene (niaD) were separately introduced into two genetic backgrounds devoid of endogenous Fot1 elements. Mobility of these copies was observed through a phenotypic assay for excision based on the restoration of nitrate reductase activity. Inactivation of the Fot1 transposase open reading frame (frameshift, deletion, or disruption) prevented excision in strains free of Fot1 elements. Molecular analysis of the Nia⁺ revertant strains showed that the Fot1 element reintegrated frequently into new genomic sites after excision and that it can transpose from the introduced niaD gene into a different chromosome. Sequence analysis of several Fot1 excision sites revealed the so-called footprint left by this transposable element. Three reinserted Fot1 elements were cloned and the DNA sequences flanking the transposon were determined using inverse polymerase chain reaction. In all cases, the transposon was inserted into a TA dinucleotide and created the characteristic TA target site duplication. The availability of autonomous Fot1 copies will now permit the development of an efficient two-component transposon tagging system comprising a trans-activator element supplying transposase and a cis-responsive marked element.

This article has been cited by other articles:

				M. Dufresne, A. Hua-Van, H. Abd el Wahab, S. B. M'Barek, C. Vasnier, L. Teysset, G. H. J. Kema, and M.-J. Daboussi Transposition of a Fungal Miniature Inverted-Repeat Transposable Element Through the Action of a Tc1-Like Transposase Genetics, January 1, 2007; 175(1): 441 - 452. [Abstract] [Full Text] [PDF]

				M.-J. Daboussi, J.-M. Daviere, S. Graziani, and T. Langin Evolution of the Fot1 Transposons in the Genus Fusarium: Discontinuous Distribution and Epigenetic Inactivation Mol. Biol. Evol., April 1, 2002; 19(4): 510 - 520. [Abstract] [Full Text] [PDF]

				A. Perl, E. Colombo, E. Samoilova, M. C. Butler, and K. Banki Human Transaldolase-associated Repetitive Elements Are Transcribed by RNA Polymerase III J. Biol. Chem., March 15, 2000; 275(10): 7261 - 7272. [Abstract] [Full Text] [PDF]