Stress-induced mobility of OPHIO1 and OPHIO2, DNA transposons of the Dutch elm disease fungi.

Abstract

The mobility of transposable elements (TEs) can contribute to genome plasticity, under- or over-expression of genes and ectopic recombination. The data collected in this study provide evidence of stress-induced mobility of OPHIO1 and OPHIO2 transposons, recently detected in Ophiostoma ulmi and O. novo-ulmi, the causal agents of Dutch elm disease (DED). The analyses of OPHIO UTRs and TIRs indicated the presence of two potential binding site motifs and a heat shock protein (hsp) promoter which could be involved in the mobility of OPHIO1 following a heat shock stress. The exact position of the hsp promoter was determined by 5' RACE PCR. After confirmation of the expression by RT-PCR of both OPHIO1 and OPHIO2 transposases in the absence of stress factors, we tested two experimental procedures to induce mobility of OPHIO TEs: (1) an exogenous (cloned) copy of OPHIO1 was introduced into the O. novo-ulmi subsp. americana strain W2 (OPHIO1 free strain) to give mutant strain W2:OPHIO1. After exposure of W2:OPHIO1 to a 55 degrees C heat shock treatment, some of the survivors showed signs of incomplete transposition (excision without reinsertion) of OPHIO1. (2) The O. novo-ulmi subsp. novo-ulmi strain AST27, introgressed from O. ulmi and carrying a distinct endogenous copy of OPHIO2 (OPHIO2-int.), was subjected to a series of abiotic stress treatments. Although a promoter sequence could not be identified, both exposures to UV light and to a 4 degrees C cold treatment caused perfect excision of OPHIO2-int. In contrast to OPHIO1, heat shock stress did not induce OPHIO2-int. mobility. Taken together, these results allow us to hypothesize a potential interspecific invasion of OPHIO transposons due to their mobility in Ophiostoma spp.

• Authors: Guillaume F Bouvet, Volker Jacobi, Karine V Plourde, Louis Bernier
• Journal: Fungal genetics and biology : FG & B (Fungal Genet Biol) Vol. 45 Issue 4 Pg. 565-78 (Apr 2008) ISSN: 1096-0937 [Electronic] United States
• PMID: 18255325 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• 5' Untranslated Regions
• DNA Transposable Elements
• RNA, Fungal
• RNA, Messenger
• Transposases

Topics

• 5' Untranslated Regions
• Ascomycota (genetics, radiation effects)
• Base Sequence
• Binding Sites
• Cold Temperature
• DNA Transposable Elements
• Hot Temperature
• Molecular Sequence Data
• Promoter Regions, Genetic
• RNA, Fungal (genetics)
• RNA, Messenger (genetics)
• Recombination, Genetic
• Transposases (biosynthesis)
• Ultraviolet Rays