scholarly journals Unusual properties of regulatory DNA from the Drosophila engrailed gene: three "pairing-sensitive" sites within a 1.6-kb region.

Genetics ◽  
1994 ◽  
Vol 136 (3) ◽  
pp. 1025-1038 ◽  
Author(s):  
J A Kassis
Keyword(s):  
Marker Gene ◽  
P Element ◽  
Drosophila Genome ◽  
Trithorax Group ◽  
Eye Color ◽  
P Elements ◽  
In Trans ◽  
Insertion Sites ◽  
Regulatory Dna ◽  
In Cis

Abstract We have previously shown that a 2-kb fragment of engrailed DNA can suppress expression of a linked marker gene, white, in the P element vector CaSpeR. This suppression is dependent on the presence of two copies of engrailed DNA-containing P elements (P[en]) in proximity in the Drosophila genome (either in cis or in trans). In this study, the 2-kb fragment was dissected and found to contain three fragments of DNA which could mediate white suppression [called "pairing-sensitive sites" (PS)]. A PS site was also identified in regulatory DNA from the Drosophila escargot gene. The eye colors of six different P[en] insertions in the escargot gene suggest an interaction between P[en]-encoded and genome-encoded PS sites. I hypothesize that white gene expression from P[en] is repressed by the formation of a protein complex which is initiated at the engrailed PS sites and also requires interactions with flanking genomic DNA. Genes were sought which influence the function of PS sites. Mutations in some Polycomb and trithorax group genes were found to affect the eye color from some P[en] insertion sites. However, different mutations affected expression from different P[en] insertion sites and no one mutation was found to affect expression from all P[en] insertion sites examined. These results suggest that white expression from P[en] is not directly regulated by members of the Polycomb and trithorax group genes, but in some cases can be influenced by them. I propose that engrailed PS sites normally act to promote interactions between distantly located engrailed regulatory sites and the engrailed promoter.

scholarly journals A fragment of engrailed regulatory DNA can mediate transvection of the white gene in Drosophila.

Genetics ◽  
1991 ◽  
Vol 128 (4) ◽  
pp. 751-761 ◽  
Author(s):  
J A Kassis ◽  
E P VanSickle ◽  
S M Sensabaugh
Keyword(s):  
Binding Sites ◽  
Marker Gene ◽  
Normal Function ◽  
P Element ◽  
Homologous Chromosomes ◽  
White Locus ◽  
In Trans ◽  
Dna Fragment ◽  
Regulatory Dna ◽  
In Cis

Abstract We have found a fragment of engrailed regulatory DNA that has an unusual effect on expression of a linked marker gene, white, in the P element transposon CaSpeR. Normally, flies homozygous for a given CaSpeR insertion have darker eyes than heterozygotes. However, when a particular engrailed DNA fragment is included in that transposon, homozygotes often have lighter eyes than heterozygotes. Thus, engrailed DNA appears to cause white expression to be repressed in homozygotes. The suppression of white is dependent on the proximity of the two transposons in the genome-either in cis (i.e., on the same chromosome) or in trans (i.e., on homologous chromosomes). Thus, the engrailed fragment is mediating a phenomenon similar to that mediated by the zeste gene at the white locus. However, the interactions we observe do not require, nor are influenced by, mutations of zeste. We suggest that the engrailed DNA contains one or more binding sites for a protein that facilitates interactions between transposons. The normal function of these sites may be to mediate interactions between distant cis-regulatory regions of engrailed, a large locus that extends over 70 kilobases.

scholarly journals Targeted transposition at the vestigial locus of Drosophila melanogaster.

Genetics ◽  
1994 ◽  
Vol 138 (4) ◽  
pp. 1127-1135
Author(s):  
T R Heslip ◽  
R B Hodgetts
Keyword(s):  
Drosophila Melanogaster ◽  
Position Effect ◽  
Regulatory Region ◽  
Current Method ◽  
P Element ◽  
Opposite Orientation ◽  
Position Effects ◽  
P Elements ◽  
In Trans ◽  
In Cis

Abstract Targeted transposition is the replacement of one P element with another. We are exploiting this unique property of P elements to study the complex regulatory domain of the Dopa decarboxylase (Ddc) gene in Drosophila melanogaster. P element constructs targeted to the same site in the genome will be subjected to the same position effect. This allows the subtle effects typical of most mutations in the Ddc regulatory region to be measured in the absence of the variable influences of position effects which are associated with the current method of germline transformation. We have investigated some of the parameters affecting targeted transposition of a Ddc transposon, P[Ddc], into a P element allele at the vestigial locus. These events were detected by an increased mutant vg phenotype. The location of the donor transposon in cis or in trans to the target had little effect on the frequency of targeting. Likewise, the mobility of different donor elements, as measured by their rate of transposition to a different chromosome, varied nearly 20-fold, while the rate of targeted transposition was very similar between them. All targeted alleles were precise replacements of the target P element by P[Ddc], but in several cases the donor was inserted in the opposite orientation. The targeted alleles could be described as the result of a replicative, conversion-like event.

The Effect of Heterologous Insertions on Gene Conversion in Mitotically Dividing Cells in Drosophila melanogaster

Genetics ◽  
2002 ◽  
Vol 161 (1) ◽  
pp. 249-258
Author(s):  
Angela M Coveny ◽  
Tammy Dray ◽  
Gregory B Gloor
Keyword(s):  
Drosophila Melanogaster ◽  
Gene Conversion ◽  
Strand Break ◽  
Double Strand Break ◽  
P Element ◽  
Double Strand Break Repair ◽  
Break Site ◽  
In Trans ◽  
Break Repair ◽  
In Cis

Abstract We examined the influence that heterologous sequences of different sizes have on the frequency of double-strand-break repair by gene conversion in Drosophila melanogaster. We induced a double-strand break on one X chromosome in female flies by P-element excision. These flies contained heterologous insertions of various sizes located 238 bp from the break site in cis or in trans to the break, or both. We observed a significant decrease in double-strand-break repair with large heterologous insertions located either in cis or in trans to the break. Reestablishing the homology by including the same heterologous sequence in cis and in trans to the double-strand break restored the frequency of gene conversion to wild-type levels. In one instance, an allelic nonhomologous insertion completely abolished repair by homologous recombination. The results show that the repair of a double-strand break by gene conversion requires chromosome pairing in the local region of the double-strand break.

scholarly journals Preferential transposition of Drosophila P elements to nearby chromosomal sites.

Genetics ◽  
1993 ◽  
Vol 133 (2) ◽  
pp. 347-359 ◽  
Author(s):  
J Tower ◽  
G H Karpen ◽  
N Craig ◽  
A C Spradling
Keyword(s):  
Gene Expression ◽  
Marker Gene ◽  
Lethal Mutation ◽  
P Element ◽  
Male And Female ◽  
Expected Frequency ◽  
P Elements ◽  
Second Screen ◽  
Marker Gene Expression ◽  
Genomic Regions

Abstract Two different schemes were used to demonstrate that Drosophila P elements preferentially transpose into genomic regions close to their starting sites. A starting element with weak rosy+ marker gene expression was mobilized from its location in the subtelomeric region of the 1,300-kb Dp1187 minichromosome. Among progeny lines with altered rosy+ expression, a much higher than expected frequency contained new insertions on Dp1187. Terminal deficiencies were also recovered frequently. In a second screen, a rosy(+)-marked element causing a lethal mutation of the cactus gene was mobilized in male and female germlines, and viable revertant chromosomes were recovered that still contained a rosy+ gene due to an intrachromosomal transposition. New transpositions recovered using both methods were mapped between 0 and 128 kb from the starting site. Our results suggested that some mechanism elevates the frequency 43-67-fold with which a P element inserts near its starting site. Local transposition is likely to be useful for enhancing the rate of insertional mutation within predetermined regions of the genome.

A genetic approach to the dissection of P transposable element functions in Drosophila

1984 ◽  
Vol 307 (1132) ◽  
pp. 231-238
Keyword(s):  
Transposable Element ◽  
Selectable Marker ◽  
Marker Gene ◽  
P Element ◽  
Genetic Approach ◽  
Selectable Marker Gene ◽  
P Elements ◽  
P Transposable Element

We have made a P element derivative that carries the selectable marker gene rosy, but which acts like a non-defective, intact P element. When introduced into an M strain fly, this element continues to transpose autonomously within the genome, and elicits certain other characteristics of hybrid dysgenesis. By mutagenizing the P element in vitro , and assaying its activity in vivo , both singly and in combination with other P elements, we have tentatively identified the regions of the element encoding the transposase function. In addition, we have examined the pattern of poly(A)+ transcripts encoded by P elements of natural P strains, and by our P element marked with rosy in transformed flies, and find two species that appear to be derived from non-defective elements, one of which may be the message for transposase.

scholarly journals P-Element-Induced Recombination in Drosophila melanogaster: Hybrid Element Insertion

Genetics ◽  
1996 ◽  
Vol 144 (4) ◽  
pp. 1601-1610 ◽  
Author(s):  
Yasmine H M Gray ◽  
Mark M Tanaka ◽  
John A Sved
Keyword(s):  
Single Unit ◽  
Target Site ◽  
P Element ◽  
High Tendency ◽  
Male Recombination ◽  
P Elements ◽  
Element Insertion ◽  
Hybrid Element ◽  
In Trans ◽  
The Right

It has previously been shown that the combination of two deleted P elements in trans, one containing the left functional end and the second element the right functional end, can lead to high levels of male recombination. This finding strongly suggests that P-element, ends from different chromosomes can become associated, followed by “pseudo-excision.” We show that two different processes are involved in resolving the pseudo-excision event: (1) the excised P-element ends continue to function as a single unit (Hybrid Element) and insert at a nearby site in the chromosome or into the element itself [Hybrid Element Insertion (HEI)] and (2) free ends that do not contain P elements repair and rejoin [(Hybrid Excision and Repair (HER)]. Both types of resolution can lead to recombination, and this paper concentrates on the HEI class. One type of HEI event predicts the exact reverse complementary duplication of an 8-bp target site, and we have confirmed the existence of such a structure in six independently derived recombinant chromosomes. There is also a high tendency for insertion events to occur within a few bases of the original 8-bp target site, including six apparent cases of insertion into the exact site.

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 An inverse PCR screen for the detection of P element insertions in cloned genomic intervals in Drosophila melanogaster.

Genetics ◽  
1995 ◽  
Vol 139 (2) ◽  
pp. 757-766 ◽  
Author(s):  
B Dalby ◽  
A J Pereira ◽  
L S Goldstein
Keyword(s):  
Drosophila Melanogaster ◽  
Large Scale ◽  
P Element ◽  
Inverse Pcr ◽  
Drosophila Genome ◽  
Screening Approach ◽  
Genes Encoding ◽  
Larval Serum Protein ◽  
Insertion Sites ◽  
Sib Selection

Abstract We developed a screening approach that utilizes an inverse polymerase chain reaction (PCR) to detect P element insertions in or near previously cloned genes in Drosophila melanogaster. We used this approach in a large scale genetic screen in which P elements were mobilized from sites on the X chromosome to new autosomal locations. Mutagenized flies were combined in pools, and our screening approach was used to generate probes corresponding to the sequences flanking each site of insertion. These probes then were used for hybridization to cloned genomic intervals, allowing individuals carrying insertions in them to be detected. We used the same approach to perform repeated rounds of sib-selection to generate stable insertion lines. We screened 16,100 insert bearing individuals and recovered 11 insertions in five intervals containing genes encoding members of the kinesin superfamily in Drosophila melanogaster. In addition, we recovered an insertion in the region including the Larval Serum Protein-2 gene. Examination by Southern hybridization confirms that the lines we recovered represent genuine insertions in the corresponding genomic intervals. Our data indicates that this approach will be very efficient both for P element mutagenesis of new genomic regions and for detection and recovery of "local" P element transposition events. In addition, our data constitutes a survey of preferred P element insertion sites in the Drosophila genome and suggests that insertion sites that are mutable at a rate of approximately 10(-4) are distributed every 40-50 kb.

scholarly journals The Berkeley Drosophila Genome Project Gene Disruption Project: Single P-Element Insertions Mutating 25% of Vital Drosophila Genes

Genetics ◽  
1999 ◽  
Vol 153 (1) ◽  
pp. 135-177 ◽  
Author(s):  
Allan C Spradling ◽  
Dianne Stern ◽  
Amy Beaton ◽  
E Jay Rhem ◽  
Todd Laverty ◽  
...  
Keyword(s):  
Gene Disruption ◽  
Genome Project ◽  
Open Reading Frames ◽  
P Element ◽  
Model Organisms ◽  
Berkeley Drosophila Genome Project ◽  
Drosophila Genome ◽  
P Elements ◽  
Wide Range ◽  
Reading Frames

AbstractA fundamental goal of genetics and functional genomics is to identify and mutate every gene in model organisms such as Drosophila melanogaster. The Berkeley Drosophila Genome Project (BDGP) gene disruption project generates single P-element insertion strains that each mutate unique genomic open reading frames. Such strains strongly facilitate further genetic and molecular studies of the disrupted loci, but it has remained unclear if P elements can be used to mutate all Drosophila genes. We now report that the primary collection has grown to contain 1045 strains that disrupt more than 25% of the estimated 3600 Drosophila genes that are essential for adult viability. Of these P insertions, 67% have been verified by genetic tests to cause the associated recessive mutant phenotypes, and the validity of most of the remaining lines is predicted on statistical grounds. Sequences flanking >920 insertions have been determined to exactly position them in the genome and to identify 376 potentially affected transcripts from collections of EST sequences. Strains in the BDGP collection are available from the Bloomington Stock Center and have already assisted the research community in characterizing >250 Drosophila genes. The likely identity of 131 additional genes in the collection is reported here. Our results show that Drosophila genes have a wide range of sensitivity to inactivation by P elements, and provide a rationale for greatly expanding the BDGP primary collection based entirely on insertion site sequencing. We predict that this approach can bring >85% of all Drosophila open reading frames under experimental control.

scholarly journals Regulation of P-Element Transposase Activity in Drosophila melanogaster by hobo Transgenes That Contain KP Elements

Genetics ◽  
2002 ◽  
Vol 161 (1) ◽  
pp. 205-215 ◽  
Author(s):  
Michael J Simmons ◽  
Kevin J Haley ◽  
Craig D Grimes ◽  
John D Raymond ◽  
Joseph C L Fong
Keyword(s):  
Drosophila Melanogaster ◽  
P Element ◽  
Drosophila Genome ◽  
Maternal Transmission ◽  
Alternate Splicing ◽  
Hsp70 Promoter ◽  
P Elements ◽  
Naturally Occurring ◽  
Element Activity ◽  
Transformation Vectors

Abstract Fusions between the Drosophila hsp70 promoter and three different incomplete P elements, KP, SP, and BP1, were inserted into the Drosophila genome by means of hobo transformation vectors and the resulting transgenic stocks were tested for repression of P-element transposase activity. Only the H(hsp/KP) transgenes repressed transposase activity, and the degree of repression was comparable to that of a naturally occurring KP element. The KP transgenes repressed transposase activity both with and without heat-shock treatments. Both the KP element and H(hsp/KP) transgenes repressed the transposase activity encoded by the modified P element in the P(ry+, Δ2-3)99B transgene more effectively than that encoded by the complete P element in the H(hsp/CP)2 transgene even though the P(ry+, Δ2-3)99B transgene was the stronger transposase source. Repression of both transposase sources appeared to be due to a zygotic effect of the KP element or transgene. There was no evidence for repression by a strictly maternal effect; nor was there any evidence for enhancement of KP repression by the joint maternal transmission of H(hsp/KP) and H(hsp/CP) transgenes. These results are consistent with the idea that KP-mediated repression of P-element activity involves a KP-repressor polypeptide that is not maternally transmitted and that KP-mediated repression is not strengthened by the 66-kD repressor produced by complete P elements through alternate splicing of their RNA.

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