Coincidence of P-Insertion Sites and Breakpoints of Deletions Induced by Activating P Elements in Drosophila

Abstract

We isolated a set of seven deletions in the 67B region by activating a nearby P-element insertion. The structures of the deletions were characterized by cloning and sequencing. The results showed that the P-induced deletions occurred nonrandomly in the genomic sites. One breakpoint of the deletions was located precisely at the end of the starting element, i.e., at the end of the inverted terminal repeats. The other breakpoint was nearby the retained starting element and coincided with preferential P-element insertion sites that harbor transcription initiation activities. It is known that P elements induce male recombination near the starting elements, giving rise to deletions with one breakpoint precisely located at an inverted terminal repeat of the retained starting element. Database analyses further revealed that deletions generated in P-induced male recombination also contained the other breakpoint in genomic regions that coincided with preferential P-insertion sites. The results suggest that nonrandom distribution of the deletion breakpoints is characteristic of the mechanism by which P elements induce deletions near the starting elements.

An Economic Overview of Ottoman State Record of Taxes: Temettuat (Profit Tax) Registers of Niğde Sanjak (1844-1845)

“…In practice, however, the rate of tithe (öşür) had varied from one-tenth to one-fifth in different places, depending on the proportion of pre-existing taxes and the yield of land in different regions 23 . Tithe, originally known to be collected from Muslims as zekât of the crops of lands 24 , was about four times as much as the Ottoman State's tax revenues 25 . It was levied not only on the grain but also on all the soil products, gardens, vineyards and even hives 26 .…”

Synthetic Lethality Induced by Toxic Polyglutamine Tract II: A Survey in Drosophila

“…Each end of the XP element contains an UAS-expression construct that is orientated in the outward direction, so it is capable of overexpressing flanking endogenous genes. Using the XP element to generate UAS-alleles that overexpress Drosophila genes is also extremely efficient, since the transposon preferentially inserts into the promoter regions of Drosophila genes [24]- [26].…”

Synthetic Lethality Induced by a Strong <i>Drosophila</i> Enhancer of Expanded Polyglutamine Tract

“…Because UAS-Dikar-a was the only Drosophila allele that showed synthetic lethality with the expanded polyQ proteins, it was necessary to determine if this rarity was associated with an unusual UAS-Dikar allele that expressed its product at a higher level than the normal UAS-alleles. For example, at a low frequency, the newly generated XP insertion could be activated by the transposase, and its structure could be altered due to a local transposition onto the XP element, followed by more complex events including gap repair [42]- [45]. These secondary events, following the initial XP element insertion in Dikar, could give rise to a stronger UAS-expression structure, by adding additional GMR sequences on top of the 5 copies of the glass-binding sites present in the XP transposon.…”

“…To address a question of whether the strong interaction was unique to the UAS-Dikar-a allele, three additional UAS-Dikar alleles were generated independently from a local transposition experiment. Local transposition occurs nearby a starting P element at high frequency and the insertion sites are nearly entirely within the promoter regions of the targeted genes [44] [45]. Thus, the characteristics of local transposition, i.e., high frequency and promoter targeting, were ideal for isolating new alleles of UAS-Dikar.…”