The Relation of Repeats to Position Effect in Drosophila Melanogaster

2004 ◽  
pp. 39-67
Author(s):  
E. B. Lewis
Keyword(s):  
Drosophila Melanogaster ◽  
Position Effect

scholarly journals Mutational Analysis of a Histone Deacetylase in Drosophila melanogaster: Missense Mutations Suppress Gene Silencing Associated With Position Effect Variegation

Genetics ◽  
2000 ◽  
Vol 154 (2) ◽  
pp. 657-668 ◽  
Author(s):  
Randy Mottus ◽  
Richard E Sobel ◽  
Thomas A Grigliatti
Keyword(s):  
Drosophila Melanogaster ◽  
Histone Deacetylase ◽  
Transcriptional Activity ◽  
Mutational Analysis ◽  
Position Effect ◽  
Transcriptional Regulator ◽  
Position Effect Variegation ◽  
Missense Mutations ◽  
Effect Variegation ◽  
New Mutations

Abstract For many years it has been noted that there is a correlation between acetylation of histones and an increase in transcriptional activity. One prediction, based on this correlation, is that hypomorphic or null mutations in histone deacetylase genes should lead to increased levels of histone acetylation and result in increased levels of transcription. It was therefore surprising when it was reported, in both yeast and fruit flies, that mutations that reduced or eliminated a histone deacetylase resulted in transcriptional silencing of genes subject to telomeric and heterochromatic position effect variegation (PEV). Here we report the first mutational analysis of a histone deacetylase in a multicellular eukaryote by examining six new mutations in HDAC1 of Drosophila melanogaster. We observed a suite of phenotypes accompanying the mutations consistent with the notion that HDAC1 acts as a global transcriptional regulator. However, in contrast to recent findings, here we report that specific missense mutations in the structural gene of HDAC1 suppress the silencing of genes subject to PEV. We propose that the missense mutations reported here are acting as antimorphic mutations that “poison” the deacetylase complex and propose a model that accounts for the various phenotypes associated with lesions in the deacetylase locus.

scholarly journals Competition Between Different Variegating Rearrangements for Limited Heterochromatic Factors in Drosophila melanogaster

Genetics ◽  
1997 ◽  
Vol 145 (4) ◽  
pp. 945-959
Author(s):  
Vett K Lloyd ◽  
Donald A Sinclair ◽  
Thomas A Grigliatti
Keyword(s):  
Drosophila Melanogaster ◽  
Chromosome Rearrangement ◽  
Position Effect ◽  
Position Effect Variegation ◽  
Euchromatic Region ◽  
Single Chromosome ◽  
Mosaic Expression ◽  
Effect Variegation ◽  
Protein Components

Position effect variegation (PEV) results from the juxtaposition of a euchromatic gene to heterochromatin. In its new position the gene is inactivated in some cells and not in others. This mosaic expression is consistent with variability in the spread of heterochromatin from cell to cell. As many components of heterochromatin are likely to be produced in limited amounts, the spread of heterochromatin into a normally euchromatic region should be accompanied by a concomitant loss or redistribution of the protein components from other heterochromatic regions. We have shown that this is the case by simultaneously monitoring variegation of a euchromatic and a heterochromatic gene associated with a single chromosome rearrangement. Secondly, if several heterochromatic regions of the genome share limited components of heterochromatin, then some variegating rearrangements should compete for these components. We have examined this hypothesis by testing flies with combinations of two or more different variegating rearrangements. Of the nine combinations of pairs of variegating rearrangements we studied, seven showed nonreciprocal interactions. These results imply that many components of heterochromatin are both shared and present in limited amounts and that they can transfer between chromosomal sites. Consequently, even nonvariegation portions of the genome will be disrupted by re-allocation of heterochromatic proteins associated with PEV. These results have implications for models of PEV.

scholarly journals A heat-shock-activated cDNA encoding GAGA factor rescues some lethal mutations in the Drosophila melanogaster Trithorax-like gene

2001 ◽  
Vol 78 (1) ◽  
pp. 13-21 ◽  
Author(s):  
H. GRANOK ◽  
B. A. LEIBOVITCH ◽  
S. C. R. ELGIN
Keyword(s):  
Drosophila Melanogaster ◽  
Heat Shock ◽  
Position Effect ◽  
Efficient Production ◽  
Position Effect Variegation ◽  
Chromosomal Protein ◽  
Gaga Factor ◽  
Genetic Rescue ◽  
Regulation Of Synthesis

GAGA factor is an important chromosomal protein involved in establishing specific nucleosome arrays and in regulating gene transcription in Drosophila melanogaster. We developed a transgenic system for controlled heat-shock-dependent overexpression of the GAGA factor 519 amino acid isoform (GAGA-519) in vivo. Efficient production of stable protein from these transgenes provided genetic rescue of a hypomorphic Trithorax-like (Trl) lethal allele to adulthood. Nevertheless, supplemental GAGA-519 did not suppress position effect variegation (PEV), a phenomenon commonly used to measure dosage effects of chromosomal proteins, nor did it rescue other lethal alleles of Trl. The results suggest requirements for the additional isoforms of GAGA factor, or for more precise regulation of synthesis, to carry out the diverse functions of this protein.

scholarly journals Transgenerational effect of drug-mediated inhibition of LSD1 on eye pigment expression in Drosophila

BMC Ecology ◽  
2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Sigrid Hoyer-Fender
Keyword(s):  
Gene Expression ◽  
Drosophila Melanogaster ◽  
Histone Modifications ◽  
Optical Measurement ◽  
Position Effect ◽  
Position Effect Variegation ◽  
Drug Induced ◽  
Lysine Specific Demethylase ◽  
Eye Colour

Abstract Background The Drosophila melanogaster mutant white-mottled is a well-established model for position-effect variegation (PEV). Transposition of the euchromatic white gene into the vicinity of the pericentric heterochromatin caused variegated expression of white due to heterochromatin spreading. The establishment of the euchromatin-heterochromatin boundary and spreading of silencing is regulated by mutually exclusive histone modifications, i.e. the methylations of histone H3 at lysine 9 and lysine 4. Demethylation of H3K4, catalysed by lysine-specific demethylase LSD1, is required for subsequent methylation of H3K9 to establish heterochromatin. LSD1 is therefore essential for heterochromatin formation and spreading. We asked whether drug-mediated inhibition of LSD affects the expression of white and if this induced change can be transmitted to those generations that have never been exposed to the triggering signal, i.e. transgenerational epigenetic inheritance. Results We used the lysine-specific demethylase 1 (LSD1)-inhibitor Tranylcypromine to investigate its effect on eye colour expression in consecutive generations by feeding the parental and F1 generations of the Drosophila melanogaster mutant white-mottled. Quantitative Western blotting revealed that Tranylcypromine inhibits H3K4-demethylation both in vitro in S2 cells as well as in embryos when used as feeding additive. Eye colour expression in male flies was determined by optical measurement of pigment extracts and qRT-PCR of white gene expression. Flies raised in the presence of Tranylcypromine and its solvent DMSO showed increased eye pigment expression. Beyond that, eye pigment expression was also affected in consecutive generations including F3, which is the first generation without contact with the inhibitor. Conclusions Our results show that feeding of Tranylcypromine and DMSO caused desilencing of white in treated flies of generation F1. Consecutive generations, raised on standard food without further supplements, are also affected by the drug-induced alteration of histone modifications. Although eye pigment expression eventually returned to the basal state, the observed long-lasting effect points to a memory capacity of previous epigenomes. Furthermore, our results indicate that food compounds potentially affect chromatin modification and hence gene expression and that the alteration is putatively inherited not only parentally but transgenerationally.

scholarly journals Modifiers of position-effect variegation in the region from 86C to 88B of the Drosophila melanogaster third chromosome

1987 ◽  
Vol 210 (3) ◽  
pp. 429-436 ◽  
Author(s):  
G. Reuter ◽  
J. Gausz ◽  
H. Gyurkovics ◽  
B. Friede ◽  
R. Bang ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Position Effect ◽  
Position Effect Variegation ◽  
Effect Variegation

scholarly journals Transcriptional Activity of the Telomeric Retrotransposon HeT-A in Drosophila melanogaster Is Stimulated as a Consequence of Subterminal Deficiencies at Homologous and Nonhomologous Telomeres

2007 ◽  
Vol 27 (13) ◽  
pp. 4991-5001 ◽  
Author(s):  
Radmila Capkova Frydrychova ◽  
Harald Biessmann ◽  
Alexander Y. Konev ◽  
Mikhail D. Golubovsky ◽  
Jessica Johnson ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Promoter Activity ◽  
Transcriptional Activity ◽  
Position Effect ◽  
Wild Type ◽  
Global Effect ◽  
Transcript Levels ◽  
Telomere Position Effect

ABSTRACT Drosophila melanogaster telomeres have two DNA domains: a terminal array of retrotransposons and a subterminal repetitive telomere-associated sequence (TAS), a source of telomere position effect (TPE). We reported previously that deletion of the 2L TAS array leads to dominant suppression of TPE by stimulating in trans expression of a telomeric transgene. Here, we compared the transcript activities of a w transgene inserted between the retrotransposon and TAS arrays at the 2L telomere in genotypes with different lengths of the 2L TAS. In contrast to individuals bearing a wild-type 2L homologue, flies with a TAS deficiency showed a significant increase in the level of telomeric w transcript during development, especially in pupae. Moreover, we identified a read-through w transcript initiated from a retrotransposon promoter in the terminal array. Read-through transcript levels also significantly increased with the presence of a 2L TAS deficiency in trans, indicating a stimulating force of the TAS deficiency on retrotransposon promoter activity. The read-through transcript contributes to total w transcript, although most w transcript originates at the w promoter. While silencing of transgenes in nonhomologous telomeres is suppressed by 2L TAS deficiencies, suggesting a global effect, the overall level of HeT-A transcripts is not increased under similar conditions.

scholarly journals Position-Effect Variegation and z1 Mediated white Repression in the In(1)wis System in Drosophila Melanogaster

Hereditas ◽  
2004 ◽  
Vol 119 (3) ◽  
pp. 209-218 ◽  
Author(s):  
Åsa Rasmuson-Lestander ◽  
Jan Larsson ◽  
Bertil Rasmuson
Keyword(s):  
Drosophila Melanogaster ◽  
Position Effect ◽  
Position Effect Variegation ◽  
Effect Variegation
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