Heavy heat shock induced retrotransposon transposition in Drosophila

Abstract

The phenomenon of transposition induction by heavy heat shock (HHS) was studied. Males of a Drosophila isogenic line with a mutation in the major gene radius incompletus (ri) were treated by HHS (37 degrees C for 1 h followed by 4 degrees C for 1 h, with the cycle repeated three times) and crossed to untreated females of the same line. The males were crossed 5 d after heat shock, and also 9 d after HHS. Many transpositions were seen in the F1 larvae by in situ hybridization. The rate of induced transposition was at least 2 orders of magnitude greater than that of the control sample, and was estimated to be 0.11 events per transposable element copy per sperm. Two 'hot' subdivisions for transpositions, induced probably during the post-meiotic stage of spermiogenesis, were found: 43B and 97DE. Three-quarters of all transpositions were localized in these positions. In other sites the rates of induced transpositions were (1.3-3.2) x 10(-2) events per occupied segment per sperm, 1 order of magnitude greater than those of the control.

Abundance, distribution and dynamics of retrotransposable elements and transposons: similarities and differences

“…Several studies of D. melanogaster report transposition rates ranging from 10 -5 to 10 -3 events/copy/generation under normal conditions for retroelements (Charlesworth et al, 1992;Nuzhdin and Mackay, 1995;Suh et al, 1995;Maside et al, 2000), about 10 -2 after heat shocks (Vasilyeva et al, 1999) and up to 10 -1 in dysgenic crosses (Seleme et al, 1999). The same orders of magnitude are reported for Class II elements, in normal and dysgenic conditions (Eggleston et al, 1988;Biémont, 1994).…”

Direct determination of the effects of genotype and extreme temperature on the transposition of roo in long-term mutation accumulation lines of Drosophila melanogaster

“…Previously, it had been shown that culture at this temperature does not mobilize transpositionally inactive TE families either (AlonsoGonzalez et al 2006). It has been reported that heavy heat shock induces transposition of roo (Zabanov et al 1994) and other retrotransposon families (Ratner et al 1992;Vasilyeva et al 1999), but the nature of the eVect of heat shock is, probably, diVerent from that of extreme but permissive temperatures. Above 28° takes place a considerable drop in fertility.…”

“…Another example of variation in TE number related with natural environmental variation was given for BARE-1 in barley (Kalendar et al 2000). In Drosophila, some retrotransposons were mobilized after heat shocks in certain laboratory lines (Ratner et al 1992;Zabanov et al 1994;Vasilyeva et al 1999), while in other experiments that eVect was not found (Arnault et al 1997). Less severe thermal stresses might have some eVect on TE activity, for example high temperature enhances transposition of the P element in dysgenic crosses (Engels and Preston 1980).…”

Direct determination of the influence of extreme temperature on transposition and structural mutation rates of Drosophila melanogaster mobile elements

“…In Drosophila, heat shocks amplify the amount of transcripts of the copia element, though without any association with transposition (Strand & McDonald, 1985). While some experiments showed that some retrotransposons are mobilized after heat shocks in certain laboratory lines (Junakovic et al, 1986;Ratner et al, 1992;Vasilyeva, Bubenshchikova & Ratner, 1999), other results showed no effect under similar stresses (Arnault, Loevenbruck & Bie´mont, 1997). In D. melanogaster, high temperature enhances transposition of the P element in dysgenic crosses (Engels & Preston, 1980).…”