• We are sorry, but NCBI web applications do not support your browser and may not function properly. More information
Logo of geneticsGeneticsCurrent IssueInformation for AuthorsEditorial BoardSubscribeSubmit a Manuscript
Genetics. Nov 1997; 147(3): 1181–1190.
PMCID: PMC1208242

Transgene Repeat Arrays Interact with Distant Heterochromatin and Cause Silencing in Cis and Trans


Tandem repeats of Drosophila transgenes can cause heterochromatic variegation for transgene expression in a copy-number and orientation-dependent manner. Here, we demonstrate different ways in which these transgene repeat arrays interact with other sequences at a distance, displaying properties identical to those of a naturally occurring block of interstitial heterochromatin. Arrays consisting of tandemly repeated white transgenes are strongly affected by proximity to constitutive heterochromatin. Moving an array closer to heterochromatin enhanced variegation, and enhancement was reverted by recombination of the array onto a normal sequence chromosome. Rearrangements that lack the array enhanced variegation of white on a homologue bearing the array. Therefore, silencing of white genes within a repeat array depends on its distance from heterochromatin of the same chromosome or of its paired homologue. In addition, white transgene arrays cause variegation of a nearby gene in cis, a hallmark of classical position-effect variegation. Such spreading of heterochromatic silencing correlates with array size. Finally, white transgene arrays cause pairing-dependent silencing of a non-variegating white insertion at the homologous position.

Full Text

The Full Text of this article is available as a PDF (3.3M).

Selected References

These references are in PubMed. This may not be the complete list of references from this article.
  • Demerec M, Slizynska H. Mottled White 258-18 of Drosophila Melanogaster. Genetics. 1937 Nov;22(6):641–649. [PMC free article] [PubMed]
  • Dernburg AF, Broman KW, Fung JC, Marshall WF, Philips J, Agard DA, Sedat JW. Perturbation of nuclear architecture by long-distance chromosome interactions. Cell. 1996 May 31;85(5):745–759. [PubMed]
  • Dobie KW, Lee M, Fantes JA, Graham E, Clark AJ, Springbett A, Lathe R, McClenaghan M. Variegated transgene expression in mouse mammary gland is determined by the transgene integration locus. Proc Natl Acad Sci U S A. 1996 Jun 25;93(13):6659–6664. [PMC free article] [PubMed]
  • Dorer DR. Do transgene arrays form heterochromatin in vertebrates? Transgenic Res. 1997 Jan;6(1):3–10. [PubMed]
  • Dorer DR, Henikoff S. Expansions of transgene repeats cause heterochromatin formation and gene silencing in Drosophila. Cell. 1994 Jul 1;77(7):993–1002. [PubMed]
  • Dorn R, Krauss V, Reuter G, Saumweber H. The enhancer of position-effect variegation of Drosophila, E(var)3-93D, codes for a chromatin protein containing a conserved domain common to several transcriptional regulators. Proc Natl Acad Sci U S A. 1993 Dec 1;90(23):11376–11380. [PMC free article] [PubMed]
  • Eberl DF, Duyf BJ, Hilliker AJ. The role of heterochromatin in the expression of a heterochromatic gene, the rolled locus of Drosophila melanogaster. Genetics. 1993 May;134(1):277–292. [PMC free article] [PubMed]
  • Festenstein R, Tolaini M, Corbella P, Mamalaki C, Parrington J, Fox M, Miliou A, Jones M, Kioussis D. Locus control region function and heterochromatin-induced position effect variegation. Science. 1996 Feb 23;271(5252):1123–1125. [PubMed]
  • Flavell RB. Inactivation of gene expression in plants as a consequence of specific sequence duplication. Proc Natl Acad Sci U S A. 1994 Apr 26;91(9):3490–3496. [PMC free article] [PubMed]
  • Gelbart WM. Synapsis-dependent allelic complementation at the decapentaplegic gene complex in Drosophila melanogaster. Proc Natl Acad Sci U S A. 1982 Apr;79(8):2636–2640. [PMC free article] [PubMed]
  • Grigliatti T. Position-effect variegation--an assay for nonhistone chromosomal proteins and chromatin assembly and modifying factors. Methods Cell Biol. 1991;35:587–627. [PubMed]
  • Henikoff S. Nuclear organization and gene expression: homologous pairing and long-range interactions. Curr Opin Cell Biol. 1997 Jun;9(3):388–395. [PubMed]
  • Henikoff S, Dreesen TD. Trans-inactivation of the Drosophila brown gene: evidence for transcriptional repression and somatic pairing dependence. Proc Natl Acad Sci U S A. 1989 Sep;86(17):6704–6708. [PMC free article] [PubMed]
  • Henikoff S, Jackson JM, Talbert PB. Distance and pairing effects on the brownDominant heterochromatic element in Drosophila. Genetics. 1995 Jul;140(3):1007–1017. [PMC free article] [PubMed]
  • Howe M, Dimitri P, Berloco M, Wakimoto BT. Cis-effects of heterochromatin on heterochromatic and euchromatic gene activity in Drosophila melanogaster. Genetics. 1995 Jul;140(3):1033–1045. [PMC free article] [PubMed]
  • Leiserson WM, Bonini NM, Benzer S. Transvection at the eyes absent gene of Drosophila. Genetics. 1994 Dec;138(4):1171–1179. [PMC free article] [PubMed]
  • Lohe AR, Hilliker AJ, Roberts PA. Mapping simple repeated DNA sequences in heterochromatin of Drosophila melanogaster. Genetics. 1993 Aug;134(4):1149–1174. [PMC free article] [PubMed]
  • Martin DI, Whitelaw E. The vagaries of variegating transgenes. Bioessays. 1996 Nov;18(11):919–923. [PubMed]
  • Martin-Morris LE, Csink AK, Dorer DR, Talbert PB, Henikoff S. Heterochromatic trans-inactivation of Drosophila white transgenes. Genetics. 1997 Oct;147(2):671–677. [PMC free article] [PubMed]
  • Milot E, Strouboulis J, Trimborn T, Wijgerde M, de Boer E, Langeveld A, Tan-Un K, Vergeer W, Yannoutsos N, Grosveld F, et al. Heterochromatin effects on the frequency and duration of LCR-mediated gene transcription. Cell. 1996 Oct 4;87(1):105–114. [PubMed]
  • Rossignol JL, Faugeron G. MIP: an epigenetic gene silencing process in Ascobolus immersus. Curr Top Microbiol Immunol. 1995;197:179–191. [PubMed]
  • Sabl JF, Henikoff S. Copy number and orientation determine the susceptibility of a gene to silencing by nearby heterochromatin in Drosophila. Genetics. 1996 Feb;142(2):447–458. [PMC free article] [PubMed]
  • Talbert PB, LeCiel CD, Henikoff S. Modification of the Drosophila heterochromatic mutation brownDominant by linkage alterations. Genetics. 1994 Feb;136(2):559–571. [PMC free article] [PubMed]
  • Tartof KD, Bishop C, Jones M, Hobbs CA, Locke J. Towards an understanding of position effect variegation. Dev Genet. 1989;10(3):162–176. [PubMed]
  • Weiler KS, Wakimoto BT. Heterochromatin and gene expression in Drosophila. Annu Rev Genet. 1995;29:577–605. [PubMed]
  • Ye F, Signer ER. RIGS (repeat-induced gene silencing) in Arabidopsis is transcriptional and alters chromatin configuration. Proc Natl Acad Sci U S A. 1996 Oct 1;93(20):10881–10886. [PMC free article] [PubMed]

Articles from Genetics are provided here courtesy of Genetics Society of America


Related citations in PubMed

See reviews...See all...

Cited by other articles in PMC

See all...


Recent Activity

Your browsing activity is empty.

Activity recording is turned off.

Turn recording back on

See more...