Cytotype Regulation by TelomericPElements inDrosophila melanogaster: Interactions WithPElements From M′ Strains

Simmons, Michael; Niemi, Jarad; Ryzek, Don-Felix; Lamour, Cecile; Goodman, Joseph W.; Kraszkiewicz, Wojciech; Wolff, Ryan

doi:10.1534/genetics.106.066670

Cited by 16 publications

(37 citation statements)

References 41 publications

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“…However, in all cases, the level of repression was not significantly affected by the presence or absence of a telomeric P element in the F 2 females themselves. Simmons et al (2007a) made similar observations.…”

Section: Expression Of Telomeric P Elementssupporting

confidence: 60%

“…The results (supplemental Table S4) indicate that in this hybrid context, TP6 was a weak repressor and TP5 was a negligible repressor. Thus, the moderate to strong repression seen in offspring of the TP-M5B#1 hybrids must be due to a synergism between the telomeric and M5B#1 P elements, as observed by Simmons et al (2007a). These results show that the native telomeric P elements, TP5 and TP6, interact synergistically with the M5B#1 P elements to repress GD, whereas the H(hsp/P) transgenes do not.…”

Section: Expression Of Telomeric P Elementsmentioning

confidence: 61%

“…Thus, there is evidence that the TP5 transgene represses sn w mutability, although less effectively than the KP transgene and much less effectively than the native TP5 element. In experiment 2, the mutation rates for the flies that carried a TP6 transgene ranged from 0.421 to 0.450-not significantly different from two of the negative controls in that (Simmons et al 2007a). TP5-N and TP6-N are strains with the native telomeric P elements on the X chromosome and are the same strains analyzed by Simmons et al (2007a); other entries are strains with H(hsp/P) transgenes that contain the indicated P element.…”

Section: Expression Of Telomeric P Elementsmentioning

confidence: 98%

“…The rationale for these tests comes from Simmons et al (2007a), who showed that the native telomeric P elements TP5 and TP6 interact synergistically with P elements from M5B#1 to repress GD induced by Harwich. We used the same experimental schemes as Simmons et al (2007a). Each transgenic strain was reciprocally crossed with M5B#1, and the F 1 hybrid females were then crossed to Harwich males to induce GD in their offspring.…”

Section: Expression Of Telomeric P Elementsmentioning

confidence: 99%

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Cytotype Regulation of P Transposable Elements in Drosophila melanogaster: Repressor Polypeptides or piRNAs?

et al. 2008

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The telomeric P elements TP5 and TP6 are associated with the P cytotype, a maternally inherited condition that represses P-element-induced hybrid dysgenesis in the Drosophila germ line. To see if cytotype repression by TP5 and TP6 might be mediated by the polypeptides they could encode, hobo transgenes carrying these elements were tested for expression of mRNA in the female germ line and for repression of hybrid dysgenesis. The TP5 and TP6 transgenes expressed more germ-line mRNA than the native telomeric P elements, but they were decidedly inferior to the native elements in their ability to repress hybrid dysgenesis. These paradoxical results are inconsistent with the repressor polypeptide model of cytotype. An alternative model based on the destruction of P transposase mRNA by Piwi-interacting (pi) RNAs was supported by finding reduced P mRNA levels in flies that carried the native telomeric P elements, which are inserted in a known major piRNA locus.T RANSPOSABLE elements are significant components of the genomes of many organisms. These elements can cause gene mutations and chromosome breakage, and over evolutionary time, they can alter the composition and structure of genomes. There is, therefore, considerable interest in elucidating the mechanisms that foster or repress their activity. For example, many researchers have studied the regulation of P transposable elements in Drosophila melanogaster-a model family of elements in a model genetic organism (Engels 1989;Rio 1990).P elements are cut-and-paste transposons whose activity is catalyzed by an 87-kDa polypeptide, the P transposase, which is encoded by complete members of the P-element family (Karess and Rubin 1984;Rio et al. 1986). This polypeptide is restricted to the germ line because the last of the element's three introns is removed from P RNA only in that tissue . In somatic cells, retention of this intron results in the production of a 66-kDa polypeptide instead of the transposase. Tissue-specific splicing is therefore an important mechanism for controlling P-element activity. However even within the germ line, where the P transposase is made, P-element activity is regulated.Genetic evidence for this regulation was obtained from early studies that defined a maternally transmitted state called cytotype (Engels 1979;Kidwell 1981). The M cytotype permits P-element activity whereas the P cytotype represses it. Thus, when P elements are combined with the M cytotype by crossing P-bearing males to M-cytotype females, the P elements are mobilized in the offspring, where they cause a syndrome of germ-line abnormalities called hybrid dysgenesis (Kidwell et al. 1977;Engels 1989). This syndrome includes gonadal dysgenesis (GD) in both of the sexes, chromosome breakage, and elevated mutation rates. By contrast, crosses between P-bearing males and P-cytotype females produce offspring that seldom show dysgenic traits. These early studies also demonstrated that the P cytotype depends on the presence of P elements themselves (Engels 1979;Sved 1987); thus, t...

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Section: Expression Of Telomeric P Elementssupporting

confidence: 60%

Section: Expression Of Telomeric P Elementsmentioning

confidence: 61%

Section: Expression Of Telomeric P Elementsmentioning

confidence: 98%

Section: Expression Of Telomeric P Elementsmentioning

confidence: 99%

See 2 more Smart Citations

Cytotype Regulation of P Transposable Elements in Drosophila melanogaster: Repressor Polypeptides or piRNAs?

et al. 2008

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“…Stuart et al (2002) added to this evidence by analyzing the regulatory abilities of two incomplete P elements, TP5 and TP6, inserted in the TAS at the left end of the X chromosome. Further study of these elements has shown that they regulate P activity in the germline but not in the soma, that their regulatory abilities are established and maintained in the female germline, that these abilities are passed on to offspring of either sex, and that, in at least some cases, they are transmitted to offspring independently of the telomeric P elements themselves Simmons et al 2004Simmons et al , 2007, accompanying article in this issue). However, neither TP5 nor TP6 appears to encode a polypeptide with any significant repressor function (Stuart et al 2002; P. Jensen, J. Stuart, M. Goodpaster, K. Newman, J. Goodman and M. Simmons, unpublished results).…”

Section: S Ince Its Discovery Bymentioning

confidence: 99%

Cytotype Regulation by TelomericPElements inDrosophila melanogaster: Evidence for Involvement of an RNA Interference Gene

et al. 2007

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P elements inserted at the left telomere of the X chromosome evoke the P cytotype, a maternally inherited condition that regulates the P-element family in the Drosophila germline. This regulation is completely disrupted in stocks heterozygous for mutations in aubergine, a gene whose protein product is involved in RNA interference. However, cytotype is not disrupted in stocks heterozygous for mutations in two other RNAi genes, piwi and homeless (spindle-E ), or in a stock heterozygous for a mutation in the chromatin protein gene Enhancer of zeste. aubergine mutations exert their effects in the female germline, where the P cytotype is normally established and through which it is maintained. These effects are transmitted maternally to offspring of both sexes independently of the mutations themselves. Lines derived from mutant aubergine stocks reestablish the P cytotype quickly, unlike lines derived from stocks heterozygous for a mutation in Suppressor of variegation 205, the gene that encodes the telomere-capping protein HP1. Cytotype regulation by telomeric P elements may be tied to a system that uses RNAi to regulate the activities of telomeric retrotransposons in Drosophila.

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A test for enhancement of cytotype regulation in Drosophila melanogaster by the transposase-encoding P Element ∆2-3

Merriman

Simmons

2013

Mol Genet Genomics

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Transposable P elements are regulated in the germ line by piRNAs, which are small RNAs that associate with the Piwi class of proteins. This regulation, called the P cytotype, is enhanced by genetic interactions between P elements that are primary sources of these RNAs and other P elements. The enhanced regulation is thought to reflect amplification of the primary piRNAs by cleavage of mRNAs derived from the other P elements through a mechanism called the ping-pong cycle. We tested the transposase-encoding P element known as ∆2-3 for its ability to enhance cytotype regulation anchored in P elements inserted at the telomere of the left arm of the X chromosome (TP elements). The ∆2-3 P element lacks the intron between exons 2 and 3 in the structurally complete P element (CP). Unlike the CP element, it does not markedly enhance cytotype regulation anchored in TP elements, nor does it transmit transposase activity through the egg cytoplasm. However, mRNAs from both the CP and ∆2-3 elements are maternally deposited in embryos. These observations suggest that maternally transmitted CP mRNA enhances cytotype regulation by participating in the ping-pong cycle and that it encodes the P transposase in the embryonic germ line, whereas maternally transmitted ∆2-3 mRNA does not, possibly because it is not efficiently directed into the primordial embryonic germ line. Strong transposon regulation may, therefore, require ping-pong cycling with maternally inherited mRNAs in the embryo.

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Cytotype Regulation by TelomericPElements inDrosophila melanogaster: Interactions WithPElements From M′ Strains

Cited by 16 publications

References 41 publications

Cytotype Regulation of P Transposable Elements in Drosophila melanogaster: Repressor Polypeptides or piRNAs?

Cytotype Regulation of P Transposable Elements in Drosophila melanogaster: Repressor Polypeptides or piRNAs?

Cytotype Regulation by TelomericPElements inDrosophila melanogaster: Evidence for Involvement of an RNA Interference Gene

A test for enhancement of cytotype regulation in Drosophila melanogaster by the transposase-encoding P Element ∆2-3

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