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 correlation between development time and variegated position effect in Drosophila melanogaster

1988 ◽  
Vol 52 (2) ◽  
pp. 119-123 ◽  
Author(s):  
John Michailidis ◽  
Neil D. Murray ◽  
Jennifer A. Marshall Graves
Keyword(s):  
Drosophila Melanogaster ◽  
Development Time ◽  
Genetic Factors ◽  
Chromosome Rearrangement ◽  
Position Effect ◽  
Position Effect Variegation ◽  
Effect Variegation ◽  
Regression Relationship ◽  
Environmental Agents ◽  
Differential Gene

SummaryPosition-effect variegation is a phenomenon in which cell-autonomous genes, normally expressed in all cells of a tissue, are expressed in some cells but not in others, leading to a mosaic tissue. Variegation occurs when a normally euchromatic gene is re-positioned close to heterochromatin by chromosome rearrangement. The extent of variegation is known to be influenced by a number of environmental and genetic factors. In the courss of investigations of the influence of the pH of larval medium on the extent of eye-colour variegation in In(1)ωm4 Drosophila melanogaster, we have found that the extent of variegation depends on development time. Flies reared at pH 2·6 develop slowly and show more extreme variegation than those reared at higher pH. This effect, as well as variations within the pH treatments, can be accounted for by differences in development time. The observed regression relationship between variegation and development time also appears to accommodate the influences of temperature on both variables. We suggest that development time may account causally for the reported influences of a number of environmental agents (temperature, crowding, chemicals) on variegation. Ways in which this might occur are discussed in the context of models of the molecular basis of differential gene activity.

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 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 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

Genes which suppress position-effect variegation in Drosophila melanogaster are clustered

1983 ◽  
Vol 191 (2) ◽  
pp. 326-333 ◽  
Author(s):  
Donald A. R. Sinclair ◽  
Randall C. Mottus ◽  
Thomas A. Grigliatti
Keyword(s):  
Drosophila Melanogaster ◽  
Position Effect ◽  
Position Effect Variegation ◽  
Effect Variegation
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