scholarly journals A P element containing suppressor of hairy-wing binding regions has novel properties for mutagenesis in Drosophila melanogaster.

Genetics ◽  
1995 ◽  
Vol 141 (3) ◽  
pp. 1061-1074 ◽  
Author(s):  
R R Roseman ◽  
E A Johnson ◽  
C K Rodesch ◽  
M Bjerke ◽  
R N Nagoshi ◽  
...  
Keyword(s):  
Gene Expression ◽  
Drosophila Melanogaster ◽  
Insertional Mutagenesis ◽  
P Element ◽  
Gypsy Element ◽  
P Elements ◽  
Structural And Functional Properties ◽  
Binding Regions ◽  
Silencer Elements ◽  
P Transposon

Abstract P elements are widely used as insertional mutagens to tag genes, facilitating molecular cloning and analyses. We modified a P element so that it carried two copies of the suppressor of Hairy-wing [su(Hw)] binding regions isolated from the gypsy transposable element. This transposon was mobilized, and the genetic consequences of its insertion were analyzed. Gene expression can be altered by the su(Hw) protein as a result of blocking the interaction between enhancer/silencer elements and their promoter. These effects can occur over long distances and are general. Therefore, a composite transposon (SUPor-P for suppressor-P element) combines the mutagenic efficacy of the gypsy element with the controllable transposition of P elements. We show that, compared to standard P elements, this composite transposon causes an expanded repertoire of mutations and produces alleles that are suppressed by su(Hw) mutations. The large number of heterochromatic insertions obtained is unusual compared to other insertional mutagenesis procedures, indicating that the SUPor-P transposon may be useful for studying the structural and functional properties of heterochromatin.

Mutations in ash1 and trx enhance P-element-dependent silencing in Drosophila melanogaster

Genome ◽  
2016 ◽  
Vol 59 (8) ◽  
pp. 527-540
Author(s):  
Allen McCracken ◽  
John Locke
Keyword(s):  
Drosophila Melanogaster ◽  
Spontaneous Mutation ◽  
Position Effect ◽  
P Element ◽  
Position Effect Variegation ◽  
Genetic Modifiers ◽  
Gypsy Element ◽  
P Elements ◽  
Opposite Action ◽  
Dose Dependent

In Drosophila melanogaster, the mini-w+ transgene in Pci is normally expressed throughout the adult eye; however, when other P or KP elements are present, a variegated-eye phenotype results, indicating random w+ silencing during development called P-element-dependent silencing (PDS). Mutant Su(var)205 and Su(var)3-7 alleles act as haplo-suppressors/triplo-enhancers of this variegated phenotype, indicating that these heterochromatic modifiers act dose dependently in PDS. Previously, we recovered a spontaneous mutation of P{lacW}ciDplac called P{lacW}ciDplacE1 (E1) that variegated in the absence of P elements, presumably due to the insertion of an adjacent gypsy element. From a screen for genetic modifiers of E1 variegation, we describe here the isolation of five mutations in ash1 and three in trx that enhance the E1 variegated phenotype in a dose-dependent and cumulative manner. These mutant alleles enhance PDS at E1, and in E1/P{lacW}ciDplac, but suppress position effect variegation (PEV) at In(1)wm4. This opposite action is consistent with a model where ASH1 and TRX mark transcriptionally active chromatin domains. If ASH1 or TRX function is lost or reduced, heterochromatin can spread into these domains creating a sink that diverts heterochromatic proteins from other variegating locations, which then may express a suppressed phenotype.

scholarly journals P-element-induced interallelic gene conversion of insertions and deletions in Drosophila melanogaster.

1993 ◽  
Vol 13 (11) ◽  
pp. 7006-7018 ◽  
Author(s):  
D M Johnson-Schlitz ◽  
W R Engels
Keyword(s):  
Drosophila Melanogaster ◽  
Gene Replacement ◽  
P Element ◽  
Element Mobility ◽  
P Elements ◽  
Insertions And Deletions ◽  
Rapid Spread ◽  
White Locus ◽  
In Cis ◽  
P Transposon

We studied the process by which whd, a P-element insertion allele of the Drosophila melanogaster white locus, is replaced by its homolog in the presence of transposase. These events are interpreted as the result of double-strand gap repair following excision of the P transposon in whd. We used a series of alleles derived from whd through P-element mobility as templates for this repair. One group of alleles, referred to collectively as whd-F, carried fragments of the P element that had lost some of the sequences needed in cis for mobility. The other group, whd-D, had lost all of the P insert and had some of the flanking DNA from white deleted. The average replacement frequencies were 43% for whd-F alleles and 7% for the whd-D alleles. Some of the former were converted at frequencies exceeding 50%. Our data suggest that the high conversion frequencies for the whd-F templates can be attributed at least in part to an elevated efficiency of repair of unexpanded gaps that is possibly caused by the closer match between whd-F sequences and the unexpanded gap endpoints. In addition, we found that the gene substitutions were almost exclusively in the direction of whd being replaced by the whd-F or whd-D allele rather than the reverse. The template alleles were usually unaltered in the process. This asymmetry implies that the conversion process is unidirectional and that the P fragments are not good substrates for P-element transposase. Our results help elucidate a highly efficient double-strand gap repair mechanism in D. melanogaster that can also be used for gene replacement procedures involving insertions and deletions. They also help explain the rapid spread of P elements in populations.

scholarly journals THE UNDERLYING BASES OF GENE EXPRESSION DIFFERENCES IN STABLE TRANSFORMANTS OF THE ROSY LOCUS IN DROSOPHILA MELANOGASTER

Genetics ◽  
1986 ◽  
Vol 113 (2) ◽  
pp. 265-285
Author(s):  
Stephen B Daniels ◽  
Margaret McCarron ◽  
Carol Love ◽  
Stephen H Clark ◽  
Arthur Chovnick
Keyword(s):  
Gene Expression ◽  
Drosophila Melanogaster ◽  
Experimental System ◽  
P Element ◽  
Breeding Line ◽  
Position Effects ◽  
Cis Acting ◽  
P Elements ◽  
Stable Transformants ◽  
True Breeding

ABSTRACT This report represents a continuation of our laboratory's effort to understand the major phenomena associated with P-M dysgenesis-mediated transformation in Drosophila. A group of stable transformants are characterized with respect to rosy gene expression. Stable, true-breeding, line-specific variants in gene expression are described. These are shown to be associated with single transposons present in each line, and the lines are free of functional P elements. The effects on expression are cis-acting, and there are no identifiable rosy DNA sequence lesions associated with these transposons. Evidence is presented that demonstrates that two features of the transformation experimental system are responsible for such variation. The first relates to the fact that the transposons insert at numerous genomic sites. Both heterochromatic and euchromatic position effects are characterized. The second relates to the fact that transformation involves dysgenic mobilization of a P-element transposon. This process is mutagenic, and such a mutation is characterized.

scholarly journals Y-Linked Male Sterile Mutations Induced by P Element in Drosophila melanogaster

Genetics ◽  
1998 ◽  
Vol 150 (2) ◽  
pp. 735-744 ◽  
Author(s):  
Ping Zhang ◽  
Rebecca L Stankiewicz
Keyword(s):  
Drosophila Melanogaster ◽  
Y Chromosome ◽  
Insertional Mutagenesis ◽  
Germ Line ◽  
Position Effect ◽  
Repetitive Sequences ◽  
P Element ◽  
Dependent Manner ◽  
Male Sterile ◽  
Structural And Functional Properties

Abstract The Y chromosome in Drosophila melanogaster is composed of highly repetitive sequences and is essential only in the male germ line. We employed P-element insertional mutagenesis to induce male sterile mutations in the Y chromosome. By using a combination of two modifiers of position effect variegation, adding an extra Y chromosome and increasing temperature, we isolated 61 P(ry+) elements in the Y chromosome. Six of these Y-linked insertions (approximately 10%) induced male sterile mutations that are mapped to two genes on the long and one on the short arms of the Y chromosome. These mutations are revertible to the wild type in a cell-autonomous and germ-line-dependent manner, consistent with previously defined Y-linked gene functions. Phenotypes associated with these P-induced mutations are similar to those resulting from deletions of the Y chromosome regions corresponding to the male fertility genes. Three alleles of the kl-3 gene on the Y long arm result in loss of the axonemal outer dynein arms in the spermatid tail, while three ks-2 alleles on the Y short arm induce defects at early postmeiotic stages. The recovery of the ms(Y) mutations induced by single P-element insertions will facilitate our effort to understand the structural and functional properties of the Y chromosome.

P-element-induced interallelic gene conversion of insertions and deletions in Drosophila melanogaster

1993 ◽  
Vol 13 (11) ◽  
pp. 7006-7018
Author(s):  
D M Johnson-Schlitz ◽  
W R Engels
Keyword(s):  
Drosophila Melanogaster ◽  
Gene Replacement ◽  
P Element ◽  
Element Mobility ◽  
P Elements ◽  
Insertions And Deletions ◽  
Rapid Spread ◽  
White Locus ◽  
In Cis ◽  
P Transposon

We studied the process by which whd, a P-element insertion allele of the Drosophila melanogaster white locus, is replaced by its homolog in the presence of transposase. These events are interpreted as the result of double-strand gap repair following excision of the P transposon in whd. We used a series of alleles derived from whd through P-element mobility as templates for this repair. One group of alleles, referred to collectively as whd-F, carried fragments of the P element that had lost some of the sequences needed in cis for mobility. The other group, whd-D, had lost all of the P insert and had some of the flanking DNA from white deleted. The average replacement frequencies were 43% for whd-F alleles and 7% for the whd-D alleles. Some of the former were converted at frequencies exceeding 50%. Our data suggest that the high conversion frequencies for the whd-F templates can be attributed at least in part to an elevated efficiency of repair of unexpanded gaps that is possibly caused by the closer match between whd-F sequences and the unexpanded gap endpoints. In addition, we found that the gene substitutions were almost exclusively in the direction of whd being replaced by the whd-F or whd-D allele rather than the reverse. The template alleles were usually unaltered in the process. This asymmetry implies that the conversion process is unidirectional and that the P fragments are not good substrates for P-element transposase. Our results help elucidate a highly efficient double-strand gap repair mechanism in D. melanogaster that can also be used for gene replacement procedures involving insertions and deletions. They also help explain the rapid spread of P elements in populations.

Transposable elements and fitness in Drosophila melanogaster

Genome ◽  
1989 ◽  
Vol 31 (1) ◽  
pp. 284-295 ◽  
Author(s):  
Trudy F. C. Mackay
Keyword(s):  
Drosophila Melanogaster ◽  
Transposable Elements ◽  
Insertional Mutagenesis ◽  
Natural Populations ◽  
P Element ◽  
Induced Mutations ◽  
P Elements ◽  
Copy Numbers ◽  
Genomic Locations

Transposable elements constitute a significant fraction of the Drosophila melanogaster genome. The five families of moderately repeated transposable elements identified to date occupy dispersed and variable genomic locations, but have relatively constant copy numbers per individual. What effect to these elements have on the fitness of the individuals harboring them? Experimental evidence relating to this question is reviewed. The relevant data fall into two broad categories. The first involves the determination of the distribution of transposable elements in natural populations, by restriction mapping or in situ hybridization, and the comparison of the observed distribution with different theoretical expectations. The second approach is to study directly the effects of new transposable element-induced mutations on fitness. The P family of transposable elements is a particularly efficient mutagen, and the results of experiments in which initially P-free chromosomes are contaminated with P elements are discussed with regard to P-induced fitness mutations.Key words: transposable elements, Drosophila melanogaster, insertional mutagenesis, fitness, P element mutagenesis, hybrid dysgenesis.

scholarly journals A hobo Transgene That Encodes the P-Element Transposase in Drosophila melanogaster: Autoregulation and Cytotype Control of Transposase Activity

Genetics ◽  
2002 ◽  
Vol 161 (1) ◽  
pp. 195-204 ◽  
Author(s):  
Michael J Simmons ◽  
Kevin J Haley ◽  
Craig D Grimes ◽  
John D Raymond ◽  
Jarad B Niemi
Keyword(s):  
Drosophila Melanogaster ◽  
Gonadal Dysgenesis ◽  
P Element ◽  
Hsp70 Gene ◽  
Alternate Splicing ◽  
Male And Female ◽  
P Elements ◽  
Male Germline ◽  
Female Germline ◽  
Transposase Expression

Abstract Drosophila were genetically transformed with a hobo transgene that contains a terminally truncated but otherwise complete P element fused to the promoter from the Drosophila hsp70 gene. Insertions of this H(hsp/CP) transgene on either of the major autosomes produced the P transposase in both the male and female germlines, but not in the soma. Heat-shock treatments significantly increased transposase activity in the female germline; in the male germline, these treatments had little effect. The transposase activity of two insertions of the H(hsp/CP) transgene was not significantly greater than their separate activities, and one insertion of this transgene reduced the transposase activity of P(ry+, Δ2-3)99B, a stable P transgene, in the germline as well as in the soma. These observations suggest that, through alternate splicing, the H(hsp/CP) transgene produces a repressor that feeds back negatively to regulate transposase expression or function in both the somatic and germline tissues. The H(hsp/CP) transgenes are able to induce gonadal dysgenesis when the transposase they encode has P-element targets to attack. However, this ability and the ability to induce P-element excisions are repressed by the P cytotype, a chromosomal/cytoplasmic state that regulates P elements in the germline.

scholarly journals The Regulatory Properties of Autonomous Subtelomeric P Elements Are Sensitive to a Suppressor of variegation in Drosophila melanogaster

Genetics ◽  
1996 ◽  
Vol 143 (4) ◽  
pp. 1663-1674 ◽  
Author(s):  
Stéphane Ronsseray ◽  
Monique Lehmann ◽  
Danielle Nouaud ◽  
Dominique Anxolabéhère
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Recombination ◽  
Natural Populations ◽  
P Element ◽  
Single Element ◽  
Heterochromatin Protein 1 ◽  
X Chromosomes ◽  
P Elements ◽  
Associated Sequences ◽  
Regulatory Properties

Abstract Genetic recombination was used in Drosophila melanogaster to isolate P elements, inserted at the telomeres of X chromosomes (cytological site 1A) from natural populations, in a genetic background devoid of other P elements. We show that complete maternally inherited P repression in the germline (P cytotype) can be elicited by only two autonomous P elements at 1A and that a single element at this site has partial regulatory properties. The analysis of the surrounding chromosomal regions of the P elements at 1A shows that in all cases these elements are flanked by Telomeric Associated Sequences, tandemly repetitive noncoding sequences that have properties of heterochromatin. In addition, we show that the regulatory properties of P elements at 1A can be inhibited by some of the mutant alleles of the Su(var)205 gene and by a deficiency of this gene. However, the regulatory properties of reference P strains (Harwich and Texas 007) are not impaired by Su(var)205 mutations. Su(var)205 encodes Heterochromatin Protein 1 (HP1). These results suggest that the HP1 dosage effect on the P element properties is sitedependent and could involve the structure of the chromatin.

scholarly journals hobo enhancer trapping mutagenesis in Drosophila reveals an insertion specificity different from P elements.

Genetics ◽  
1993 ◽  
Vol 135 (4) ◽  
pp. 1063-1076 ◽  
Author(s):  
D Smith ◽  
J Wohlgemuth ◽  
B R Calvi ◽  
I Franklin ◽  
W M Gelbart
Keyword(s):  
Drosophila Melanogaster ◽  
Transposable Element ◽  
Enhancer Trap ◽  
P Element ◽  
Present Evidence ◽  
P Elements ◽  
Element Insertion ◽  
Enhancer Trapping ◽  
Indispensable Tool

Abstract P element enhancer trapping has become an indispensable tool in the analysis of the Drosophila melanogaster genome. However, there is great variation in the mutability of loci by these elements such that some loci are relatively refractory to insertion. We have developed the hobo transposable element for use in enhancer trapping and we describe the results of a hobo enhancer trap screen. In addition, we present evidence that a hobo enhancer trap element has a pattern of insertion into the genome that is different from the distribution of P elements in the available database. Hence, hobo insertion may facilitate access to genes resistant to P element insertion.

scholarly journals A novel repressor of P element transposition in Drosophila melanogaster

1998 ◽  
Vol 71 (1) ◽  
pp. 21-30 ◽  
Author(s):  
RICHARD M. BADGE ◽  
JOHN F. Y. BROOKFIELD
Keyword(s):  
Drosophila Melanogaster ◽  
Inbred Line ◽  
Gonadal Dysgenesis ◽  
Full Length ◽  
P Element ◽  
Temperature Dependent ◽  
P Elements

We have discovered, in an inbred line (Loua) of Drosophila melanogaster from Zaïre, a third chromosome showing unusual P element repression. Repression of P element transposition by this chromosome, named Loua3, is dominant zygotic and has three unusual properties. Firstly, its repression of the gonadal dysgenesis caused by a strong P haplotype is strongly temperature-dependent, being most evident at higher rearing temperatures. Secondly, subdivision of Loua3 by recombination abolishes repression: the effect is apparently a function of the intact chromosome. Finally, Loua3 also diminishes somatic lethality when chromosomes carrying many ‘ammunition’ elements (Birmingham2) are exposed to the constitutive transposase source Δ2-3(99B). The chromosome has 17 P elements, none full-length, located in at least 12 dispersed positions.

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