Transvection and chromosomal trans-interaction effects

Pirrotta, Vincenzo

doi:10.1016/s0304-419x(99)00019-0

Cited by 44 publications

(54 citation statements)

References 27 publications

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“…However, other instances of transvection that are insensitive to mutations in z, such as those observed at Scr, Abd-B, and vg (Hopmann et al 1995;Southworth and Kennison 2002;Coulthard et al 2005), have been identified. These observations, coupled with the fact that z null mutants are viable and do not have notably disrupted chromosome pairing (Goldberg et al 1989;Pirrotta 1999), suggest that parallel or redundant mechanisms must exist for maintaining somatic chromosome pairing.…”

Section: Ugo35mentioning

confidence: 99%

Enhancer Blocking and Transvection at the DrosophilaapterousLocus

et al. 2008

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Intra-and interchromosomal interactions have been implicated in a number of genetic phenomena in diverse organisms, suggesting that the higher-order structural organization of chromosomes in the nucleus can have a profound impact on gene regulation. In Drosophila, homologous chromosomes remain paired in somatic tissues, allowing for trans interactions between genes and regulatory elements on the two homologs. One consequence of homolog pairing is the phenomenon of transvection, in which regulatory elements on one homolog can affect the expression of a gene in trans. We report a new instance of transvection at the Drosophila apterous (ap) locus. Two different insertions of boundary elements in the ap regulatory region were identified. The boundaries are inserted between the ap wing enhancer and the ap promoter and have highly penetrant wing defects typical of mutants in ap. When crossed to an ap promoter deletion, both boundary inserts exhibit the interallelic complementation characteristic of transvection. To confirm that transvection occurs at ap, we generated a deletion of the ap wing enhancer by FRT-mediated recombination. When the wing-enhancer deletion is crossed to the ap promoter deletion, strong transvection is observed. Interestingly, the two boundary elements, which are inserted $10 kb apart, fail to block enhancer action when they are present in trans to one another. We demonstrate that this is unlikely to be due to insulator bypass. The transvection effects described here may provide insight into the role that boundary element pairing plays in enhancer blocking both in cis and in trans.

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Section: Ugo35mentioning

confidence: 99%

Enhancer Blocking and Transvection at the DrosophilaapterousLocus

et al. 2008

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“…Although most extensively studied in the Dipteran insect Drosophila melanogaster, nonmeiotic association of homologous chromosomal regions has also been observed elsewhere, where it participates in gene expression and other vital processes (reviewed by Wu and Morris 1999;Duncan 2002;Grant-Downton and Dickinson 2004;Mckee 2004;Zickler 2006). Importantly, nonmeiotic pairing can influence gene regulation and DNA repair through the processes of transvection (reviewed by Pirrotta 1999;Wu and Morris 1999;Duncan 2002;Kassis 2002;Kennison and Southworth 2002) and recombination (reviewed by Gloor 2002;Wyman et al 2004; also see Rong and Golic 2003), respectively. Pairing of homologous chromosomal regions has also been implicated in mammalian X-inactivation (Marahrens 1999;Bacher et al 2006;Diaz-Perez et al 2006;Xu et al 2006) and imprinting (Lasalle and Lalande 1996;Riesselmann and Haaf 1999).…”

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confidence: 99%

“…For example, zeste, which encodes a transcription factor, was identified as a gene that modifies transvectionassociated phenotypes of several loci (reviewed by Pirrotta 1999;Wu and Morris 1999;Duncan 2002;Kennison and Southworth 2002). Interestingly, zeste protein shows a propensity to self-aggregate, suggesting that it may promote pairing by binding to chromosomes and pulling or holding them together (Chen and Pirrotta 1993).…”

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confidence: 99%

Disruption of Topoisomerase II Perturbs Pairing in Drosophila Cell Culture

Williams¹,

Bateman²,

Novikov³

et al. 2007

Genetics

111

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Homolog pairing refers to the alignment and physical apposition of homologous chromosomal segments. Although commonly observed during meiosis, homolog pairing also occurs in nonmeiotic cells of several organisms, including humans and Drosophila. The mechanism underlying nonmeiotic pairing, however, remains largely unknown. Here, we explore the use of established Drosophila cell lines for the analysis of pairing in somatic cells. Using fluorescent in situ hybridization (FISH), we assayed pairing at nine regions scattered throughout the genome of Kc 167 cells, observing high levels of homolog pairing at all six euchromatic regions assayed and variably lower levels in regions in or near centromeric heterochromatin. We have also observed extensive pairing in six additional cell lines representing different tissues of origin, different ploidies, and two different species, demonstrating homolog pairing in cell culture to be impervious to cell type or culture history. Furthermore, by sorting Kc 167 cells into G 1 , S, and G 2 subpopulations, we show that even progression through these stages of the cell cycle does not significantly change pairing levels. Finally, our data indicate that disrupting Drosophila topoisomerase II (Top2) gene function with RNAi and chemical inhibitors perturbs homolog pairing, suggesting Top2 to be a gene important for pairing.

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“…2-7, and reviewed in refs. [8][9][10][11]. These observations suggest that transvection may be generally possible for eukaryotic control regions and that these processes may be important for the normal regulation of some genes.…”

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confidence: 99%

Enhancer action in trans is permitted throughout the Drosophila genome

Chen

Huisinga

Viering

et al. 2002

Proc. Natl. Acad. Sci. U.S.A.

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Interactions between paired homologous genes can lead to changes in gene expression. Such trans-regulatory effects exemplify transvection and are displayed by many genes in Drosophila, in which homologous chromosomes are paired somatically. Transvection involving the yellow cuticle pigmentation gene can occur by at least two mechanisms, one involving the trans-action of enhancers on a paired promoter and a second involving pairingmediated bypass of a chromatin insulator. A system was developed to evaluate whether the action of the yellow enhancers in trans could be reconstituted outside of the natural near telomeric location of the yellow gene. To this end, transgenic flies were generated that carried a yellow gene modified by the inclusion of strategically placed recognition sites for the Cre and FLP recombinases. Independent action of the recombinases produced a pair of derivative alleles, one enhancerless and the other promoterless, at each transgene location. Transvection between the derivatives was assessed by the degree of interallelic complementation. Complementation was observed at all eight sites tested. These studies demonstrate that yellow transvection can occur at multiple genomic locations and indicate that the Drosophila genome generally is permissive to enhancer action in trans. G ene expression is controlled by regulatory elements that modulate transcription in appropriate temporal and spatial patterns. In eukaryotes, these control elements often reside in large, complex regions, requiring action over long distances to elicit changes in transcription of a target promoter. In some cases, the control elements of paired homologous genes can interact in trans to alter gene expression. Such trans-regulatory effects illustrate processes known as transvection. Transvection was described first in Drosophila (1), which has homologous chromosomes that are paired somatically. Transvection and related processes have been reported in many organisms besides Drosophila (for example, refs. 2-7, and reviewed in refs. 8-11). These observations suggest that transvection may be generally possible for eukaryotic control regions and that these processes may be important for the normal regulation of some genes. For example, chromosomal pairing is proposed to play a role in gene silencing associated with imprinting and X chromosome inactivation (4, 12).In Drosophila, interactions between homologous chromosomes can have either a positive or negative effect on transcription. Examples of negative effects include repression of white gene expression by certain alleles of zeste, trans silencing conferred by the insertion of a block of heterochromatin near the brown gene, and pairing-dependent silencing, as exemplified by the effects of Polycomb response elements (reviewed in refs. 8-11, 13, and 14). Examples of positive effects include events at the Ultrabithorax, Abdominal B, decapentaplegic, yellow, and eyes absent genes (1,(15)(16)(17)(18)(19)(20)(21)(22)(23)(24).A useful system for studying the mechanisms involved in posi...

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Transvection and chromosomal trans-interaction effects

Cited by 44 publications

References 27 publications

Enhancer Blocking and Transvection at the DrosophilaapterousLocus

Enhancer Blocking and Transvection at the DrosophilaapterousLocus

Disruption of Topoisomerase II Perturbs Pairing in Drosophila Cell Culture

Enhancer action in trans is permitted throughout the Drosophila genome

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