Molecular analysis of the neurogenic locus mastermind of Drosophila melanogaster.

Genetics ◽  
1988 ◽  
Vol 118 (3) ◽  
pp. 483-497
Author(s):  
B Yedvobnick ◽  
D Smoller ◽  
P Young ◽  
D Mills
Keyword(s):  
Molecular Analysis ◽  
Genomic Dna ◽  
Transcriptional Activity ◽  
Chromosome Breakage ◽  
P Element ◽  
Minimal Size ◽  
Position Effects ◽  
P Elements ◽  
Preliminary Study ◽  
Element Sequence

Abstract The neurogenic loci comprise a small group of genes which are required for proper division between the neural and epidermal pathways of differentiation within the neuroectoderm. Loss of neurogenic gene function results in the misrouting of prospective epidermal cells into neuroblasts. A molecular analysis of the neurogenic locus mastermind (mam) has been initiated through transposon tagging with P elements. Employing the Harwich strain as the source of P in a hybrid dysgenesis screen, 6000 chromosomes were tested for the production of lethal mam alleles and eight mutations were isolated. The mam region is the site of residence of a P element in Harwich which forms the focus of a chromosome breakage hotspot. Hybrid dysgenic induced mam alleles elicit cuticular and neural abnormalities typical of the neurogenic phenotype, and in five of the eight cases the mutants appear to retain a P element in the cytogenetic region (50CD) of mam. Utilizing P element sequence as probe, mam region genomic DNA was cloned and used to initiate a chromosome walk extending over 120 kb. The physical breakpoints associated with the hybrid dysgenic alleles fall within a 60-kb genomic segment, predicting this as the minimal size of the mam locus barring position effects. The locus contains a high density of repeated elements of two classes; opa (CAX)n and (dC-dA)n.(dG-dT)n. A preliminary study of the transcriptional activity of the mam region is presented.

scholarly journals Germ-line and somatic recombination induced by in vitro modified P elements in Drosophila melanogaster.

Genetics ◽  
1990 ◽  
Vol 124 (2) ◽  
pp. 331-337 ◽  
Author(s):  
J A Sved ◽  
W B Eggleston ◽  
W R Engels
Keyword(s):  
Drosophila Melanogaster ◽  
Germ Line ◽  
Somatic Cells ◽  
Chromosome Breakage ◽  
P Element ◽  
Male Germ Line ◽  
Male Recombination ◽  
P Elements ◽  
Somatic Recombination

Abstract The P element insertion delta 2-3(99B) has previously been shown to activate incomplete P elements elsewhere in the genome. We show that this element, in conjunction with a second incomplete P element, P[CaSpeR], also induces recombination in the male germ line. The recombination is induced preferentially in the region of the P[CaSpeR] element. Recombinant chromosomes contain the P[CaSpeR] element in more than 50% of cases, and alternative models of transposon replication and preferential chromosome breakage are put forward to explain this finding. As is the case with male recombination induced by P-M dysgenic crosses, recombination appears to be premeiotic in a high proportion of cases. The delta 2-3(99B) element is known to act in somatic cells. Correspondingly, we show that the delta 2-3(99B)-P[CaSpeR] combination elevates the incidence of somatic recombination.

scholarly journals A genetic and molecular analysis of the 46C chromosomal region surrounding the FMRFamide neuropeptide gene in Drosophila melanogaster.

Genetics ◽  
1994 ◽  
Vol 137 (1) ◽  
pp. 121-137
Author(s):  
M A O'Brien ◽  
M S Roberts ◽  
P H Taghert
Keyword(s):  
Drosophila Melanogaster ◽  
Molecular Analysis ◽  
Chromosomal Region ◽  
Small Region ◽  
Complementation Group ◽  
P Element ◽  
X Ray ◽  
P Elements ◽  
Complementation Groups ◽  
Gene Maps

Abstract We have analyzed the FMRFamide neuropeptide gene region of Drosophila melanogaster. This gene maps to the 46C region of chromosome 2R; this interval previously was not well characterized. For this genetic and molecular analysis, we have used X-ray mutagenesis, EMS mutagenesis, and the recently reported local P element transposition method. We identified four overlapping deletions, two of which have proximal breakpoints that define a 50-60-kb region surrounding the FMRFamide gene in 46C. To this small region, we mapped three lethal complementation groups; 10 additional lethal complementation groups were mapped to more distal regions of 46CD. One of these groups corresponds to even-skipped, the other 12 are previously unidentified. Using various lines of evidence we excluded the possibility that FMRFamide corresponds to any of the three lethal complementation groups mapping to its immediate 50-60-kb vicinity. The positions of two of the three lethal complementation groups were identified with P elements using a local transposition scheme. The third lethal complementation group was excluded as being FMRFamide mutants by sequence analysis and by immunocytochemistry with proFMRFamide precursor-specific antibodies. This analysis has (1) provided a genetic map of the 46CD chromosomal region and a detailed molecular map of a portion of the 46C region and (2) provided additional evidence of the utility of local transposition for targeting nearby genes.

scholarly journals Disgenesia do híbrido em populações naturais de Drosophila melanogaster.

1999 ◽  
Vol 21 (21) ◽  
pp. 51 ◽  
Author(s):  
Chirlei Cintia Klein ◽  
Liliana Essi ◽  
Ronaldo Medeiros Golombieski ◽  
Élgion Lúcio da Silva Loreto
Keyword(s):  
Drosophila Melanogaster ◽  
Molecular Analysis ◽  
Natural Populations ◽  
Rio Grande ◽  
P Element ◽  
Rio Grande Do Sul ◽  
Genetic Traits ◽  
P Elements ◽  
Regulatory Capacity ◽  
Element Activity

Hybrid dysgenesis has been defined as a remarkable syndrome of correlated genetic traits that are produced in some particular crosses between certain strains. The present study main objective was classify recently collected Drosophila melanogaster strains in relation to P element activity and regulatory capacity. Our results to natural populations trapped from Rio Grande do Sul, Brazil and Colombia shows that it fell on Q class, since all examinated strains has showed P elements by molecular analysis and low P activity. In the same way, these strains shows low susceptibility to P element action. The bigger values found in the colombian population are in agreement with the clinal hypothesis to P element activity.

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.

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 Somatic Effects of P Element Activity in Drosophila melanogaster: Pupal Lethality

Genetics ◽  
1987 ◽  
Vol 117 (4) ◽  
pp. 745-757
Author(s):  
William R Engels ◽  
Wendy K Benz ◽  
Christine R Preston ◽  
Patricia L Graham ◽  
Randall W Phillis ◽  
...  
Keyword(s):  
Strong Dependence ◽  
Somatic Cells ◽  
Pupal Stage ◽  
Lethal Effect ◽  
Chromosome Breakage ◽  
P Element ◽  
Transposase Gene ◽  
P Elements ◽  
Larval Stages ◽  
Disc Cells

ABSTRACT Nonautonomous P elements normally excise and transpose only when a source of transposase is supplied, and only in the germline. The germline specificity depends on one of the introns of the transposase gene which is not spliced in somatic cells. To study the effects of somatic P activity, a modified P element (Δ2-3) lacking this intron was used as a source of transposase. Nonautonomous P elements from a strain called Birmingham, when mobilized in somatic cells by Δ2-3, were found to cause lethality, although neither component was lethal by itself. The three major Birmingham chromosomes acted approximately independently in producing the lethal effect. This lethality showed a strong dependence on temperature. Although temperature sensitivity was limited to larval stages, the actual deaths occurred at the pupal stage. Survivors, which could be recovered by decreasing the temperature or by reducing the proportion of the Birmingham genome present, often showed multiple developmental anomalies and reduced longevity reminiscent of the effects of cell death from radiation damage. Although the genetic damage occurred in dividing imaginal disc cells, the phenotypic manifestations—death and abnormalities—are not observed until later. The survivors also showed gonadal dysgenic (GD) sterility, a well-known characteristic of P-M hybrid dysgenesis. To explain these findings, we suggest that pupal lethality and GD sterility are both caused by massive chromosome breakage in larval cells, resulting from excision and transposition of genomic P elements acting as substrate for the transposase.

scholarly journals Distribution and structure of cloned P elements from the Drosophila melanogaster P strain π2

1992 ◽  
Vol 60 (1) ◽  
pp. 33-41 ◽  
Author(s):  
Kevin O'Hare ◽  
Alan Driver ◽  
Stephen McGrath ◽  
Dena M. Johnson-Schiltz
Keyword(s):  
Drosophila Melanogaster ◽  
Transposable Elements ◽  
Dna Sequence ◽  
Genomic Library ◽  
Single Copy ◽  
P Element ◽  
Base Pairs ◽  
Single Base ◽  
P Elements ◽  
Element Sequence

SummaryP transposable elements of Drosophila melanogaster cloned from the strong P strain π2 have been analysed. The structures and chromosomal locations of 26 of the 30–50 elements estimated to be present in π2 have been determined. At one location two elements are inserted 100 base pairs (bp) apart, and in a second location two elements are only separated by the 8 bp duplicated upon P-element insertion. In addition to 2.9 kilobasepair (kbp) elements, elements with 14 different internal deletions from 1.3 to 2.3 kbp in size have been isolated. There are 7 copies of the 2–9 kbp element, 2 copies each of 5 internally deleted elements and a single copy of 9 internally deleted elements. One of the elements found twice is the KP element, which may play a role in the regulation of hybrid dysgenesis in strains which contain many copies of this element. Apart from internal deletions the elements are extremely homogeneous in DNA sequence, with only 2 single base polymorphisms detected twice each in over 16 kbp of P-element sequence. Although transpositions are infrequent in an inbred P cytotype strain such as π2, the distribution of these cloned elements indicates that when the genomic library was made, the strain was polymorphic with respect to element location. The distribution and structures of the element are discussed with respect to models for regulation of P-element transposition.

scholarly journals P-Element Repression in Drosophila melanogaster by a Naturally Occurring Defective Telomeric P Copy

Genetics ◽  
2000 ◽  
Vol 155 (4) ◽  
pp. 1841-1854 ◽  
Author(s):  
Laurent Marin ◽  
Monique Lehmann ◽  
Danielle Nouaud ◽  
Hassan Izaabel ◽  
Dominique Anxolabéhère ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Hybrid Dysgenesis ◽  
P Element ◽  
Tunisian Population ◽  
P Elements ◽  
Naturally Occurring ◽  
Dependent Component ◽  
Associated Sequences ◽  
Element Sequence

Abstract In Drosophila melanogaster, hybrid dysgenesis occurs in progeny from crosses between females lacking P elements and males carrying P elements scattered throughout the genome. We have genetically isolated a naturally occurring P insertion at cytological location 1A, from a Tunisian population. The Nasr'Allah-P(1A) element [NA-P(1A)] has a deletion of the first 871 bp including the P promoter. It is flanked at the 3′ end by telomeric associated sequences and at the 5′ end by a HeT-A element sequence. The NA-P(1A) element strongly represses dysgenic sterility and P transposition. However, when testing P-promoter repression, NA-P(1A) was unable to repress a germinally expressed P-lacZ construct bearing no 5′-homology with it. Conversely, a second P-lacZ construct, in which the fusion with lacZ takes place in exon 3 of P, was successfully repressed by NA-P(1A). This suggests that NA-P(1A) repression involves a homology-dependent component.

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.

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