Transcription activates repressed domains in theDrosophilabithorax complex

A series of mutations have been recovered in the bithorax complex of D. melanogaster that transform the first segment of the abdomen into a copy of the second or third abdominal segment. These dominantUltraabdominal alleles are all associated with P element insertions which are transcribed in the first abdominal segment. The transcripts proceed past the end of the P element for up to 50 kb, extending through the regulatory regions for the second and third abdominal segments. Blocking transcription from the P element promoter reverts the mutant phenotype. Previously identified Ultraabdominal alleles, not associated with P elements, also show abnormal transcription of the same region.

Download Full-text

Enhancer traps in the Drosophila bithorax complex mark parasegmental domains.

Genetics ◽

10.1093/genetics/138.2.387 ◽

1994 ◽

Vol 138 (2) ◽

pp. 387-399

Author(s):

K McCall ◽

M B O'Connor ◽

W Bender

Keyword(s):

Protein Pattern ◽

Polycomb Group ◽

P Element ◽

Homeotic Genes ◽

Bithorax Complex ◽

Lacz Expression ◽

Regulatory Regions ◽

P Elements ◽

Endogenous Genes ◽

Beta Galactosidase

Abstract Eight P elements carrying a beta-galactosidase (lacZ) reporter have been mapped to sites within the Drosophila bithorax complex. The bithorax complex contains three homeotic genes, and at least nine regulatory regions which control their expression in successive parasegments of the fly. The enhancer traps inserted at the promoter of one of the genes, Ultrabithorax, express lacZ in patterns which mimic the Ultrabithorax protein pattern. Enhancer traps in the regulatory regions do not mimic the endogenous genes, but express lacZ globally in the relevant parasegments. Some P elements carry large DNA fragments upstream of the lacZ promoter but internal to the P element. In cases where these internal sequences specify a lacZ pattern, that pattern is generally suppressed when the element is inserted in the bithorax complex. In embryos mutant for genes of the Polycomb group, the lacZ expression from the enhancer traps spreads to all segments. Thus, the enhancer traps reveal parasegmental domains that are maintained by Polycomb-mediated repression. Such domains may be realized by parasegmental differences in chromatin structure.

Download Full-text

Interactions of Drosophila Ultrabithorax Regulatory Regions With Native and Foreign Promoters

Genetics ◽

10.1093/genetics/145.1.123 ◽

1997 ◽

Vol 145 (1) ◽

pp. 123-137 ◽

Cited By ~ 5

Author(s):

Fernando Casares ◽

Welcome Bender ◽

John Merriam ◽

Ernesto Sánchez-Herrero

Keyword(s):

P Element ◽

Lacz Gene ◽

Bithorax Complex ◽

Lacz Reporter ◽

Normal Pattern ◽

Lacz Reporter Gene ◽

Regulatory Regions ◽

Long Range Interactions ◽

In Trans ◽

Dependent Interaction

The Ultrabithorax (Ubx) gene of the Drosophila bithorax complex is required to specify parasegments 5 and 6. Two P-element “enhancer traps” have been recovered within the locus that contain the bacterial lacZ gene under the control of the P-element promoter. The P insertion that is closer to the Ubx promoter expresses lucZ in a pattern similar to that of the normal Ubx gene, but also in parasegment 4 during embryonic development. Two deletions have been recovered that remove the normal Ubx promoter plus several kilobases on either side, but retain the lacZ reporter gene. The lacZ patterns from the deletion derivatives closely match the normal pattern of Ubx expression in late embryos and imaginal discs. The lacZ genes in the deletion derivatives are also negatively regulated by Ubx and activated in trans by Contrabithorax mutations, again like the normal Ubx gene. Thus, the deleted regions, including several kilobases around the Ubx promoter, are not required for long range interactions with Ubx regulatory regions. The deletion derivatives also stimulate transvection, a pairing-dependent interaction with the Ubx promoter on the homologous chromosome.

Download Full-text

An intact RNA interference pathway is required for expression of the mutant wing phenotype of vg21-3, a P-element-induced allele of the vestigial gene in Drosophila

Genome ◽

10.1139/g2012-016 ◽

2012 ◽

Vol 55 (4) ◽

pp. 312-326 ◽

Cited By ~ 1

Author(s):

Ross B. Hodgetts ◽

Sandra L. O’Keefe ◽

Kyle J. Anderson

Keyword(s):

Rna Interference ◽

Dna Sequencing ◽

Mutant Phenotype ◽

P Element ◽

Type I ◽

P Elements ◽

Gene Encode ◽

Interference Response ◽

Partial Reversion

We have determined that two P elements, P[21-3] and P[21r36], residing in the 5′-UTR of the vestigial wing gene, encode functional repressors in eye tissue. However, neither element fits a previous categorization of repressor-making elements as Type I or II. Both elements encode polypeptides that are shorter than the canonical elements they most closely resemble. DNA sequencing reveals that P[21r36] encodes an intact THAP domain that is missing in the P[21] element, which does not encode a functional repressor. Recovery of P[21-3] at sites other than vestigial (where it causes the wing mutant, vg21-3) reveals that the element can make repressor in wing tissue of sufficient activity to repress the mutant phenotype of vg21-3. Why the P[21-3] element fails to produce repressor when located at vestigial may be explained by our observation that three different mutants in the RNA interference pathway cause a partial reversion of vg21-3. We speculate that the vg and P-initiated transcripts that arise at the vg locus in the vg21-3 mutant trigger an RNA interference response that results in the mutual degradation of both transcripts.

Download Full-text

Paternal imprinting of inversion Uab1 causes homeotic transformations in Drosophila.

Genetics ◽

10.1093/genetics/118.1.103 ◽

1988 ◽

Vol 118 (1) ◽

pp. 103-107

Author(s):

D T Kuhn ◽

G Packert

Keyword(s):

Maternal Effect ◽

Abdominal Segment ◽

Mutant Phenotype ◽

Dependent Manner ◽

Bithorax Complex ◽

Gain Of Function ◽

Modifying Genes ◽

Paternal Transmission ◽

Genital Disc

Abstract Paternal transmission of the bithorax-complex (BX-C) rearrangement, inversion Uab1, causes a specific dominant gain of function phenotype in most abdominal segments. This represents a case of paternal imprinting since the mutant phenotype will occur only if inversion Uab1 is paternally transmitted. The transformations in males are toward genital arch tissue. For females the transformations are to tissue found on abdominal segment 7 (Ab7) and to structures normally restricted to the genital disc. Ninety-six percent of transformed areas appear on Ab5 and Ab6 in both sexes and on Ab7 in females, coinciding with the Abd-B domain. Four percent of the transformations occurred on Ab1 through Ab4, coinciding with the abd-A domain. The mutant phenotype can be dramatically enhanced by modifying genes such as the posterior BX-C mutant tuh-3. Expressivity is modulated by maternal effect alleles interacting with tuh-3. A region of function within inversion Uab1 appears to be programmed during spermatogenesis to function in a legacy dependent manner during embryogenesis.

Download Full-text

Novel events associated with phenotypic reversion of a P element mutant in Drosophila melanogaster

Genome ◽

10.1139/g06-065 ◽

2006 ◽

Vol 49 (9) ◽

pp. 1184-1192 ◽

Cited By ~ 3

Author(s):

Kyle J. Anderson ◽

Monica M. Davis ◽

Ross B. Hodgetts

Keyword(s):

Drosophila Melanogaster ◽

Mutagenic Activity ◽

Transposon Mutagenesis ◽

Mutant Phenotype ◽

P Element ◽

Interesting Aspect ◽

Internal Deletion ◽

P Elements ◽

Element Evolution ◽

Phenotypic Reversion

Transposable P elements have been used extensively for Drosophila mutagenesis. While their mutagenic activity has long been recognized, the mechanisms by which P elements cause mutations are varied and not completely understood. We describe here an experiment to replace a P element at vestigial (vg) that caused a strong mutant phenotype (P[21-3]) with a P element (P[21]) known to produce a very weak phenotype when inserted at vg. In addition to testing the feasibility of P element replacements at vg, our investigation led to the production of 7 new vg alleles and 1 apparent second site suppressor. All the vg21-3 revertants that we recovered had a P element inserted into the first exon of vg at the same location and in the same orientation as the original element in vg21-3, providing a unique opportunity to study the mechanism of transposon mutagenesis. A majority of the revertants arose from a previously described event: internal deletion of P sequences, including the P promoter. In addition, 3 novel reversions of the vg21-3 wing phenotype were recovered. The wings of homozygous vg21r36 flies were normal. However, vg21r36 in combination with a deletion of the vg locus exhibited a strong mutant wing phenotype. This was surprising, because the P element insertion in vg21r36 was very similar to that found in the vg21 allele, which showed only slight nicking of the wings in combination with a deletion. In vg21r4, reversion was caused by a tandem insertion of P[21] and the original P[21-3] element present in vg21-3. Finally, the vg21r7 revertant had a P[21-3] insert at vg and 3 additional P elements elsewhere in the genome. We hypothesize that reversion in the 3 novel cases might be caused by P repressor produced by an element at vg or, in the case of vg21r7, elsewhere in the genome. This raises an interesting aspect of P element evolution. While P transposons produce mutations that might prove deleterious to their host, their success in invading the genome of D. melanogaster may be explained by their ability to silence those same mutations by a range of repressor-producing elements.

Download Full-text

P element homing to the Drosophila bithorax complex

Development ◽

10.1242/dev.127.18.3981 ◽

2000 ◽

Vol 127 (18) ◽

pp. 3981-3992 ◽

Cited By ~ 1

Author(s):

W. Bender ◽

A. Hudson

Keyword(s):

Selectable Marker ◽

Transcription Unit ◽

P Element ◽

Bithorax Complex ◽

Lacz Reporter ◽

P Elements ◽

Insertion Sites ◽

Dna Fragment ◽

Beta Galactosidase ◽

Chromosome Regions

P elements containing a 7 kb DNA fragment from the middle of the Drosophila bithorax complex insert preferentially into the bithorax complex or into the adjacent chromosome regions. This ‘homing’ property is similar to that reported for the engrailed promoter (Hama, C., Ali, Z. and Kornberg, T. B. (1990) Genes Dev. 4, 1079–1093). The 7 kb fragment does not contain any known promoter, but it acts as a boundary element separating adjacent segmental domains. An enhancer-trap P element was constructed with the homing fragment and the selectable marker flanked by FRT sites. P insertions can be trimmed down by Flp-mediated recombination to just the lacZ reporter, so that the (beta)-galactosidase pattern is not influenced by sequences inside the P element. Twenty insertions into the bithorax complex express (beta)-galactosidase in segmentally limited patterns, reflecting the segmental domains of the bithorax complex where the elements reside. The mapping of segmental domains has now been revised, with enlargement of the abx/bx, bxd/pbx, and the iab-3 domains. The FRT sites in the P elements permit recombination between pairs of elements on opposite chromosomes, to generate duplications or deletions of the DNA between the two insertion sites. Using this technique, the length of the Ultrabithorax transcription unit was varied from 37 to 138 kb, but there was surprisingly little effect on Ultrabithorax function.

Download Full-text

The oxen Gene of Drosophila Encodes a Homolog of Subunit 9 of Yeast Ubiquinol-Cytochrome c Oxidoreductase Complex: Evidence for Modulation of Gene Expression in Response to Mitochondrial Activity

Genetics ◽

10.1093/genetics/156.4.1727 ◽

2000 ◽

Vol 156 (4) ◽

pp. 1727-1736 ◽

Cited By ~ 2

Author(s):

Maxim V Frolov ◽

Elizaveta V Benevolenskaya ◽

James A Birchler

Keyword(s):

Gene Expression ◽

Cytochrome C ◽

Cellular Response ◽

Insertion Site ◽

Nuclear Gene ◽

Mutant Phenotype ◽

P Element ◽

Mitochondrial Activity ◽

Genes Encoding ◽

Subunit 9

Abstract A P-element insertion in the oxen gene, ox1, has been isolated in a search for modifiers of white gene expression. The mutation preferentially exerts a negative dosage effect upon the expression of three genes encoding ABC transporters involved in pigment precursor transport, white, brown, and scarlet. A precise excision of the P element reverts the mutant phenotype. Five different transcription units were identified around the insertion site. To distinguish a transcript responsible for the mutant phenotype, a set of deletions within the oxen region was generated. Analysis of gene expression within the oxen region in the case of deletions as well as generation of transgenic flies allowed us to identify the transcript responsible for oxen function. It encodes a 6.6-kD homolog of mitochondrial ubiquinol cytochrome c oxidoreductase (QCR9), subunit 9 of the bc1 complex in yeast. In addition to white, brown, and scarlet, oxen regulates the expression of three of seven tested genes. Thus, our data provide additional evidence for a cellular response to changes in mitochondrial function. The oxen mutation provides a model for the genetic analysis in multicellular organisms of the effect of mitochondrial activity on nuclear gene expression.

Download Full-text

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

Genetics ◽

10.1093/genetics/161.1.195 ◽

2002 ◽

Vol 161 (1) ◽

pp. 195-204 ◽

Cited By ~ 1

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.

Download Full-text

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

Genetics ◽

10.1093/genetics/143.4.1663 ◽

1996 ◽

Vol 143 (4) ◽

pp. 1663-1674 ◽

Cited By ~ 3

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.

Download Full-text

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

Genetics ◽

10.1093/genetics/135.4.1063 ◽

1993 ◽

Vol 135 (4) ◽

pp. 1063-1076 ◽

Cited By ~ 2

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.

Download Full-text