Position effect variegation in <i>Drosophila</i>: Towards a genetics of chromatin assembly

Eissenberg, Joel C.

doi:10.1002/bies.950110105

Cited by 138 publications

(59 citation statements)

References 30 publications

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“…Variegated expression of a euchromatic gene is seen when a chromosomal rearrangement places it next to heterochromatin (for recent reviews, see Eissenberg 1989;Tartof et al 1989;Henikoff 1990;Reuter and Spierer 1992). This PEV is dependent on genetic elements like the Y chromosome and suppressor and enhancer loci.…”

Section: The Variegated Phenotype Induced By Ph Regulatory Sequences mentioning

confidence: 99%

polyhomeotic regulatory sequences induce developmental regulator-dependent variegation and targeted P-element insertions in Drosophila.

Fauvarque¹,

Dura²

1993

Genes Dev.

188

123

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Section: The Variegated Phenotype Induced By Ph Regulatory Sequences mentioning

confidence: 99%

polyhomeotic regulatory sequences induce developmental regulator-dependent variegation and targeted P-element insertions in Drosophila.

Fauvarque¹,

Dura²

1993

Genes Dev.

188

123

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“…Furthermore, the polytenization level of the heterochromatin adjacent to the breakpoint was never monitored. Although the apparent discrepancies may have reflected the fact that different rearrangements and genetic backgrounds were studied, many workers have concluded that differential polytenization does not contribute significantly to the genetic defects in variegating rearrangements, and that changes in chromosome morphology result primarily from altered condensation (reviewed by Eissenberg, 1989).…”

Section: A Variegated Position Effect Reduces the Copy Number Of Somementioning

confidence: 99%

“…Chromosome rearrangements that juxtapose euchromatic and heterochromatic regions in plants, mammals, and Dipterans frequently inhibit the function of nearby genes on a cell-bycell basis (reviewed in Lewis, 1950;Spofford, 1976;Eissenberg, 1989). Genetic and cytological studies in Drosophila melanogaster demonstrated distinctive and perplexing general features of such "position-effect variegation."…”

Section: Introductionmentioning

confidence: 99%

Reduced DNA polytenization of a minichromosome region undergoing position-effect variegation in Drosophila

Karpen¹,

Spradling²

1990

Cell

125

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SummaryMolecular analysis of a Drosophila minichromosome, Dp(1;f)1187, revealed a relationship between position-effect variegation and the copy number reductions of heterochromatic sequences that occur in polytene cells. Heterochromatin adjacent to a defined junction with euchromatin underpolytenized at least 60-fold. Lesser reductions were observed in euchromatic sequences up to 103 kb from the breakpoint. The copy number changes behaved in all respects like the expression of yellow, a gene located within the affected region. Both copy number and yellow expression displayed a cell-by-cell mosaic pattern of reduction, and adding a Y chromosome, a known suppressor of variegation, increased both substantially. We discuss the possibility that changes in replication alter copy number locally and also propose an alternative model of position-effect variegation based on the somatic elimination of heterochromatic sequences.

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“…1A). Regarding the integration site, the randomly integrated transgene is susceptible to "position effect variegation (PEV)" that often causes impaired transgene expression and in worst cases, complete gene silencing [2,19]. PEV is caused by the presence of cis-regulatory sequences and/or the local chromatin configuration at the integration site [75].…”

Section: Introductionmentioning

confidence: 99%

PITT: Pronuclear Injection-Based Targeted Transgenesis, a Reliable Transgene Expression Method in Mice

et al. 2012

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Transgenic (Tg) mice have been extensively used as valuable tools for analyses of gene function and have also served as models for many human diseases. Typically, a transgenic mouse is created by microinjection of DNA into pronuclei in which the DNA gets integrated at random locations in the genome. Frequently however, the random integration of multiple copies of a transgene results in transgene silencing, probably because of a positional effect and/or repeat-induced gene silencing. The transgene silencing issue has been overcome by single-copy transgene integration into a predetermined locus through ES cell-mediated transgenesis, despite it being expensive and more time-consuming compared with pronuclear injection (PI)-mediated transgenesis. Recently, several groups have reported novel approaches that employ PI for targeted transgenesis. They are based on site-specific recombination catalyzed by a recombinase or an integrase or homologous recombination enhanced by a zinc-finger nuclease via PI. These next-generation transgenesis methods, which we termed as PI-based Targeted Transgenesis (PITT), are more convenient and faster than ES cell-based transgenesis. Furthermore, the Tg mice generated by these newer methods contain a single-copy transgene and exhibit reliable expression of the transgene. The objective of this review is to present the recent progress in mouse targeted transgenesis.

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Position effect variegation in Drosophila: Towards a genetics of chromatin assembly

Cited by 138 publications

References 30 publications

polyhomeotic regulatory sequences induce developmental regulator-dependent variegation and targeted P-element insertions in Drosophila.

polyhomeotic regulatory sequences induce developmental regulator-dependent variegation and targeted P-element insertions in Drosophila.

Reduced DNA polytenization of a minichromosome region undergoing position-effect variegation in Drosophila

PITT: Pronuclear Injection-Based Targeted Transgenesis, a Reliable Transgene Expression Method in Mice

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