Molecular analysis of hybrid dysgenesis-induced derivatives of a P-element allele at the vg locus

Secondary and tertiary derivatives of a P-element insertion allele at the vestigial (vg) locus were induced by hybrid dysgenesis. The derivatives were characterized by Southern analyses and, in four cases, by DNA sequencing. The alterations found were P-element internal deletions, deletions of the insert and/or adjacent vg region DNA, or novel insertions of P-element sequences into existing P-element inserts. The relatively high frequency of secondary insertions into P-element sequences observed herein is unusual, since secondary insertions have seldom been recovered in other dysgenic screens. The effects of the alleles on vg expression were determined. The results are consistent with a model in which the insertions disrupt vg gene expression by transcriptional interference.

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Mutation in P0, a Dual Function Ribosomal Protein/Apurinic/Apyrimidinic Endonuclease, Modifies Gene Expression and Position Effect Variegation in Drosophila

Genetics ◽

10.1093/genetics/150.4.1487 ◽

1998 ◽

Vol 150 (4) ◽

pp. 1487-1495

Author(s):

Maxim V Frolov ◽

James A Birchler

Keyword(s):

Gene Expression ◽

Ribosomal Protein ◽

Position Effect ◽

P Element ◽

Dual Function ◽

Insertion Mutant ◽

Position Effect Variegation ◽

Element Insertion ◽

Effect Variegation ◽

Ribosomal Protein P0

Abstract In a search for modifiers of gene expression with the white eye color gene as a target, a third chromosomal P-element insertion mutant l(3)01544 has been identified that exhibits a strong pigment increase in a white-apricot background. Molecular analysis shows that the P-element insertion is found in the first intron of the gene surrounding the insertion site. Sequencing both the cDNA and genomic fragments revealed that the identified gene is identical to one encoding ribosomal protein P0/apurinic/apyrimidinic endonuclease. The P-element-induced mutation, l(3)01544, affects the steady-state level of white transcripts and transcripts of some other genes. In addition, l(3)01544 suppresses the variegated phenotypes of In(1)wm4h and In(1)y3P, suggesting a potential involvement of the P0 protein in modifying position effect variegation. The revertant generated by the precise excision of the P element has lost all mutant phenotypes. Recent work revealed that Drosophila ribosomal protein P0 contains an apurinic/apyrimidinic endonuclease activity. Our results suggest that this multifunctional protein is also involved in regulation of gene expression in Drosophila.

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A particular P-element insertion is correlated to the P-induced hybrid dysgenesis repression in Drosophila melanogaster

Genetics Research ◽

10.1017/s0016672300030627 ◽

1992 ◽

Vol 60 (1) ◽

pp. 15-24 ◽

Cited By ~ 5

Author(s):

Dominique Higuet ◽

Dominique Anxolabéhére ◽

Danielle Nouaud

Keyword(s):

Drosophila Melanogaster ◽

Promoter Activity ◽

Hybrid Dysgenesis ◽

P Element ◽

P Elements ◽

Element Insertion ◽

Element Number

SummaryTransposable P elements in Drosophila melanogaster cause hybrid dysgenesis if their mobility is not repressed. The ability to regulate the dysgenic activity of the P elements depends on several mechanisms, one of which hypothesized that a particular deleted P element (the KP element) results in a non-susceptibility which is biparentally transmitted. In this study totally nonsusceptible lines, and susceptible lines containing exclusively KP elements (IINS2 line and IIS2 line) were isolated from a M' strain. We show that non-susceptibility is correlated with a particular insertion of one KP element located at the cytological site 47D1. The repression ability of the GD sterility is determined by a recessive chromosomal factor, and cannot be due to the KP-element number. Here the repression of the P mobility is associated with reduction of the P transcripts and the inhibition of P promoter activity.

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Molecular cloning of suppressor of sable, a Drosophila melanogaster transposon-mediated suppressor.

Molecular and Cellular Biology ◽

10.1128/mcb.6.5.1520 ◽

1986 ◽

Vol 6 (5) ◽

pp. 1520-1528 ◽

Cited By ~ 14

Author(s):

D Y Chang ◽

B Wisely ◽

S M Huang ◽

R A Voelker

Keyword(s):

Drosophila Melanogaster ◽

Dna Sequences ◽

Insertion Site ◽

Hybrid Dysgenesis ◽

P Element ◽

Dna Transformation ◽

Wild Type ◽

Induced Mutations ◽

X Ray ◽

Element Insertion

A hybrid dysgenesis-induced allele [su(s)w20] associated with a P-element insertion was used to clone sequences from the su(s) region of Drosophila melanogaster by means of the transposon-tagging technique. Cloned sequences were used to probe restriction enzyme-digested DNAs from 22 other su(s) mutations. None of three X-ray-induced or six ethyl methanesulfonate-induced su(s) mutations possessed detectable variation. Seven spontaneous, four hybrid dysgenesis-induced, and two DNA transformation-induced mutations were associated with insertions within 2.0 kilobases (kb) of the su(s)w20 P-element insertion site. When the region of DNA that included the mutational insertions was used to probe poly(A)+ RNAs, a 5-kb message was detected in wild-type RNA that was present in greatly reduced amounts in two su(s) mutations. By using strand-specific probes, the direction of transcription of the 5-kb message was determined. The mutational insertions lie in DNA sequences near the 5' end of the 5-kb message. Three of the seven spontaneous su(s) mutations are associated with gypsy insertions, but they are not suppressible by su(Hw).

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A selective screen to recover chromosomal deletions and duplications in Drosophila melanogaster.

Genetics ◽

10.1093/genetics/119.2.377 ◽

1988 ◽

Vol 119 (2) ◽

pp. 377-390

Author(s):

D Gubb ◽

S McGill ◽

M Ashburner

Keyword(s):

Drosophila Melanogaster ◽

Chromosomal Region ◽

Molecular Level ◽

Hybrid Dysgenesis ◽

P Element ◽

Genomic Clones ◽

Element Insertion ◽

Chromosomal Deletions ◽

Complementation Groups ◽

Insertion Sites

Abstract A screen is described that will select for breakpoints within a restricted chromosomal region in Drosophila. The aberrations recovered can be used to construct chromosomes carrying synthetic duplications and deletions. Such chromosomes have applications in the mapping of complementation groups at both the genetic and molecular level. In particular, breakpoints recovered after P element hybrid dysgenesis tend to be associated with P element insertion sites. Such aberration breakpoints can be genetically mapped, as synthetic deletions, and then used as transposon-tagged sites for the recovery of genomic clones.

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An insulator blocks access to enhancers by an illegitimate promoter, preventing repression by transcriptional interference

PLoS Genetics ◽

10.1371/journal.pgen.1009536 ◽

2021 ◽

Vol 17 (4) ◽

pp. e1009536

Author(s):

Miki Fujioka ◽

Anastasiya Nezdyur ◽

James B. Jaynes

Keyword(s):

Gene Expression ◽

Heat Shock ◽

P Element ◽

Gene Repression ◽

Transcriptional Interference ◽

Promoter Specificity ◽

Functional Units

Several distinct activities and functions have been described for chromatin insulators, which separate genes along chromosomes into functional units. Here, we describe a novel mechanism of functional separation whereby an insulator prevents gene repression. When thehomieinsulator is deleted from the end of a Drosophilaeven skipped(eve) locus, a flanking P-element promoter is activated in a partialevepattern, causing expression driven by enhancers in the 3’ region to be repressed. The mechanism involves transcriptional read-through from the flanking promoter. This conclusion is based on the following. Read-through driven by a heterologous enhancer is sufficient to repress, even whenhomieis in place. Furthermore, when the flanking promoter is turned around, repression is minimal. Transcriptional read-through that does not produce anti-sense RNA can still repress expression, ruling out RNAi as the mechanism in this case. Thus, transcriptional interference, caused by enhancer capture and read-through when the insulator is removed, repressesevepromoter-driven expression. We also show that enhancer-promoter specificity and processivity of transcription can have decisive effects on the consequences of insulator removal. First, a coreheat shock 70promoter that is not activated well byeveenhancers did not cause read-through sufficient to repress theevepromoter. Second, these transcripts are less processive than those initiated at the P-promoter, measured by how far they extend through theevelocus, and so are less disruptive. These results highlight the importance of considering transcriptional read-through when assessing the effects of insulators on gene expression.

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P element insertions and rearrangements at the singed locus of Drosophila melanogaster.

Genetics ◽

10.1093/genetics/119.1.75 ◽

1988 ◽

Vol 119 (1) ◽

pp. 75-83

Author(s):

H Roiha ◽

G M Rubin ◽

K O'Hare

Keyword(s):

Drosophila Melanogaster ◽

High Frequency ◽

The Other ◽

Hybrid Dysgenesis ◽

P Element ◽

Wild Type ◽

Tandem Arrangement ◽

P Elements

Abstract DNA from the singed gene of Drosophila melanogaster was isolated using an inversion between a previously cloned P element at cytological location 17C and the hypermutable allele singed-weak. Five out of nine singed mutants examined have alterations in their DNA maps in this region. The singed locus is a hotspot for mutation during P-M hybrid dysgenesis, and we have analyzed 22 mutations induced by P-M hybrid dysgenesis. All 22 have a P element inserted within a 700-bp region. The precise positions of 10 P element insertions were determined and they define 4 sites within a 100-bp interval. During P-M hybrid dysgenesis, the singed-weak allele is destabilized, producing two classes of phenotypically altered derivatives at high frequency. In singed-weak, two defective P elements are present in a "head-to-head" or inverse tandem arrangement. Excision of one element results in a more extreme singed bristle phenotype while excision of the other leads to a wild-type bristle phenotype.

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Genetic and Molecular Analysis of the Spm-dependent a-m2 Alleles of the Maize a Locus

Genetics ◽

10.1093/genetics/117.1.117 ◽

1987 ◽

Vol 117 (1) ◽

pp. 117-137

Author(s):

Patrick Masson ◽

Richard Surosky ◽

Jeffrey A Kingsbury ◽

Nina V Fedoroff

Keyword(s):

Gene Expression ◽

Transposable Element ◽

Gene Product ◽

Molecular Analysis ◽

Regulatory Mechanism ◽

Transposable Element Family ◽

Genetic Organization ◽

Derivatives Of ◽

Negative Regulatory Mechanism ◽

Insight Into

ABSTRACT The Suppressor-mutator (Spm) transposable element family of maize consists of the fully functional standard Spm (Spm-s) and many mutant elements. Insertion of an Spm element in or near a gene can markedly alter its expression, in some cases bringing the gene under the control of the mechanisms that regulate expression of the element. To gain insight into such mechanisms, as well as to enlarge our understanding of the Spm element's genetic organization, we have analyzed derivatives of a unique Spm insertion at the maize a locus in which the gene is co-expressed and co-regulated with the element. We describe the genetic properties and the structure of the a locus and Spm element in 9 strains (collectively designated the a-m2 alleles) selected by McClintock from the original a-m2 allele for heritable changes affecting either the Spm element or expression of the a gene. Most of the mutations are intra-element deletions within the 8.3-kb Spm element; many alter both Spm function and expression of the gene. Spm controls a gene expression in alleles with internally deleted, transposition-defective Spm elements and element ends contain the target sequences that mediate Spm's ability to activate expression of the gene. We argue that the properties of the a-m2 alleles reflect the operation of an element-encoded positive regulatory mechanism, as well as a negative regulatory mechanism that affects expression of the element, but appears not to be mediated by an element-encoded gene product.

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Molecular analysis of an unstable P element insertion at the singed locus of Drosophila melanogaster: evidence for intracistronic transposition of a P element.

Genetics ◽

10.1093/genetics/119.1.85 ◽

1988 ◽

Vol 119 (1) ◽

pp. 85-94

Author(s):

R S Hawley ◽

R A Steuber ◽

C H Marcus ◽

R Sohn ◽

D M Baronas ◽

...

Keyword(s):

Drosophila Melanogaster ◽

Detailed Analysis ◽

Chromosome Aberration ◽

Sister Chromatid ◽

High Frequency ◽

P Element ◽

Wild Type ◽

P Elements ◽

Element Insertion ◽

Inverted Orientation

Abstract In a companion study, a number of P element insertions into the singed locus were characterized. Here is reported a detailed analysis of the structure and mutability of another P element insertion at sn, known as sncm. Under conditions which mobilize P elements, sncm mutates at high frequency to both wild-type (sn+) and to a much more extreme allele (snext). Wild-type revertants appear to represent precise or nearly precise excisions of the P element. Certainly two, and most likely all five, of the snext alleles studied result from the insertion of a duplicate copy of this P element into a nearby site in an inverted orientation. We propose a model in which both the sn+ and snext mutational events can be explained by excision of the P element from one chromatid followed by reintegration into the sister chromatid at a nearby site (intracistronic transposition). Finally, it is shown that the snext alleles are themselves unstable and the structure of a resulting chromosome aberration is examined.

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Molecular cloning of suppressor of sable, a Drosophila melanogaster transposon-mediated suppressor

Molecular and Cellular Biology ◽

10.1128/mcb.6.5.1520-1528.1986 ◽

1986 ◽

Vol 6 (5) ◽

pp. 1520-1528

Author(s):

D Y Chang ◽

B Wisely ◽

S M Huang ◽

R A Voelker

Keyword(s):

Drosophila Melanogaster ◽

Dna Sequences ◽

Insertion Site ◽

Hybrid Dysgenesis ◽

P Element ◽

Dna Transformation ◽

Wild Type ◽

Induced Mutations ◽

X Ray ◽

Element Insertion

A hybrid dysgenesis-induced allele [su(s)w20] associated with a P-element insertion was used to clone sequences from the su(s) region of Drosophila melanogaster by means of the transposon-tagging technique. Cloned sequences were used to probe restriction enzyme-digested DNAs from 22 other su(s) mutations. None of three X-ray-induced or six ethyl methanesulfonate-induced su(s) mutations possessed detectable variation. Seven spontaneous, four hybrid dysgenesis-induced, and two DNA transformation-induced mutations were associated with insertions within 2.0 kilobases (kb) of the su(s)w20 P-element insertion site. When the region of DNA that included the mutational insertions was used to probe poly(A)+ RNAs, a 5-kb message was detected in wild-type RNA that was present in greatly reduced amounts in two su(s) mutations. By using strand-specific probes, the direction of transcription of the 5-kb message was determined. The mutational insertions lie in DNA sequences near the 5' end of the 5-kb message. Three of the seven spontaneous su(s) mutations are associated with gypsy insertions, but they are not suppressible by su(Hw).

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