Stocks for studying repression of P element transposition
Updated April 11, 2016
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P element transposition is repressed when P transposase is not produced or its action is inhibited. Repression occurs by two mechanisms. First, P elements located near the X chromosome telomere are transcribed in both sense and antisense directions to initiate an RNAi-like mechanism to eliminate transposase mRNA produced by all P elements in the genome. This mechanism may also alter chromatin to repress transposition. Second, peptide repressors are produced from P element sequences that prevent P transcription or transposition. P elements with different internal sequences deleted are useful for examining both modes of P repression.

Strains that can repress the production or action of P transposase are said to have P cytotype. They are identified by <P> in the genotype. Most stocks in the Bloomington collection lack P repression and, consequently, have M cytotype. Crosses between M and P strains can produce hybrid dysgenesis in progeny from mobilization of P insertions. We recommend that you familiarize yourself with P element biology before making crosses with P cytotype stocks.

Papers relevant to these stocks are listed at the bottom of the page.

See Stocks Useful for Transposable Element Mutagenesis for stocks with transgenes expressing P transposase constitutively.

Stocks with full-length P elements

These are the stocks with full-length P elements most relevant to the study of P transposition. We have a ~16 other stocks with mutations or deletions produced by hybrid dysgenesis that carry autonomous P element insertions, but they are not listed on this webpage.

Stock # Genotype
2384 pi[[2]] <P>
2395 TM6B-P/pi[[2]] <P>
3995 pi[[2]]/CyO, amos[Roi-1] cn[2P] bw[1] <P>
64159 y[1] w[67c23]; H{w[+mC]=hsp/CP}2
64160 y[1] w[67c23]; H{w[+mC]=hsp/CP}3
64166 y[1] w[67c23]; H{w[+mC]=hsp/KP}3; Harwich <P>
64177 y[1] w[67c23]; Harwich <P>

The double brackets in pi[[2]] denote the subscripting of "2". (It is the only subscripted genetic element in Bloomington stocks.)

Stocks with P transposase or P repressor “sensor” mutations

sn[w] produces a weak “singed" bristle phenotype due to the presence of two naturally occurring, nonautonomous P insertions. Upon excision of one P element, the weak singed phenotype will change to a nearly wild type bristle phenotype. Upon excision of the other P element, the weak singed phenotype will change to a more extremely gnarled bristle phenotype.

sn[50e] produces a strong singed bristle phenotype in the absence of P repressor peptide and a weak phenotype in its presence.

Stock # Genotype
2541 sn[w]; ry[506]
3001 y[1] sn[w]; bw[1]; st[1]
64179 y[1] w[67c23] sn[50e]

Stocks with telomeric insertions of internally deleted P elements

The only P elements present in these stocks are the telomeric insertions and the P insertions associated with sn[w]. Crossing these flies to M cytotype flies will not result in hybrid dysgenesis, because the transposase genes have been disrupted. Nevertheless, these flies have P cytotype because the telomeric insertions can repress transposition of autonomous P elements.

Stock # Genotype
64168 P{TP5}1A1 w[1] <P>
64169 P{TP6}1A1 w[1] <P>
64170 P{NA}1A w[sp1] <P>
64171 P{TP5}1A1 w[1] sn[w] <P>
64172 P{TP6}1A1 w[1] sn[w] <P>
64173 P{NA}1A w[67c23] sn[w] <P>

Stocks with internally deleted P elements located at nontelomeric sites

Stock # Genotype
2539 Birmingham; Sb[1]/TM6
64163 y[1] w[67c23]; H{w[+mC]=hsp-TP5}D
64164 y[1] w[67c23]; H{w[+mC]=hsp-TP6}A
64165 y[1] w[67c23]; H{w[+mC]=hsp/KP}3
64166 y[1] w[67c23]; H{w[+mC]=hsp/KP}3; Harwich <P>
64167 w[*]; H{w[+mC]=hsp-Pstar}B
64174 w[1] sn[w] P{KP}13F
64175 y[1] w[67c23]; H{w[+mC]=KP}H
64178 Sexi.6
64419 y[1] w[67c23]; H{w[+mC]=KP}C

Papers discussing the regulation of P transposition

Engels (1989) P elements in Drosophila melanogaster. In Mobile DNA (ed. D. E. Berg and M. M. Howe), pp. 437-484. Washington, D. C.: American Society for Microbiology Publications.

Ronsseray et al. (1991) The maternally inherited regulation of P elements in Drosophila melanogaster can be elicited by two P copies at cytological site 1A on the X chromosome. Genetics 129: 501-512.

Marin et al. (2000) P-element repression in Drosophila melanogaster by a naturally occurring defective telomeric P copy. Genetics 155:1841-1854.

Stuart et al. (2002) Telomeric P elements associated with cytotype regulation of the P transposon family in Drosophila melanogaster. Genetics 162: 1641-1654.

Brennecke et al. (2008) An epigenetic role for maternally inherited piRNAs in transposon silencing. Science 322: 1387-1392.

Jensen et al. (2008) Cytotype regulation of P transposable elements in Drosophila melanogaster: repressor polypeptides or piRNAs? Genetics 179: 1785-1793.

Simmons et al. (2012) Maternal enhancement of cytotype regulation in Drosophila melanogaster by genetic interactions between telomeric P elements and non-telomeric P elements. Genet. Res. Camb. 94: 339-351.

Simmons et al. (2014) Genetic interactions between P elements involved in piRNA-mediated repression of hybrid dysgenesis in Drosophila melanogaster. Genes, Genomes, Genetics 4: 1417-1427.

Simmons et al. (2015) Transposon regulation in Drosophila: piRNA-producing P elements facilitate repression of hybrid dysgenesis by a P element that encodes a repressor polypeptide. Mol. Genet. Genomics 290: 127-140.