Abstract
We examined the genetic, morphological, and molecular effects of position effect variegation inDrosophila, and the effects of mutations that either suppress [Su(var)] or enhance [E(var)] this phenomenon. All eightSu(var) mutations examined strongly suppress the inactivation of variegating alleles of the genes white [In(l) w m4], brown [In (2R)bw VDe2] and Stubble [T(2;3)Sb V]. TheE(var) mutation enhances variegation of these loci. The chromosomal region 3C-E (26 bands) which includes the white locus is usually packaged as heterochromatin in salivary glands of the variegating strainw m4. Addition of any of theSu(var) mutations restores a more euchromatic morphology to this region. In situ hybridization to polytene chromosomes and DNA blot analyses of gene copy number demonstrate that the DNA of thew + gene is less accessible to its probe in the variegatingw m4 strain than it is in the wildtype or variegation-suppressed strains. Blot analysis of larval salivary gland DNA indicates that the white gene copy number does not vary among the strains. Hence, the differences in binding of thew + gene probe in the variegating and variegation-suppressed strains reflect differences in chromosomal packaging rather than alterations in gene number. The effects of variegation and theSu(var) mutations on chromatin structure were analyzed further by DNAse I digestion and DNA blot hybridization. In contrast to their dramatic effects on chromosomal morphology and gene expression, theSu(var) mutations had negligible effects on nuclease sensitivity of the white gene chromatin. We suggest that the changes in gene expression resulting from position effect variegation and the action of theSu(var) mutations involve alterations in chromosomal packaging.
Similar content being viewed by others
References
Ananiev EV, Gvozdev VA (1974) Changed pattern of transcription and replication in polytene chromosomes ofDrosophila melanogaster resulting from euheterochromatin rearrangement. Chromosoma 45:173–191
Bahn E (1971) Position-effect variegation for an isoamylase inDrosophila melanogaster. Hereditas 67:79–82
Clark SH, Chovnick A (1986) Studies of normal and position-affected expression of rosy region genes inDrosophila melanogaster. Genetics 114:819–840
Cribbs DL, Leung J, Newton CH, Hayashi S, Miller RC Jr, Tener GM (1987) Extensive microheterogeneity of serine tRNA genes fromDrosophila melanogaster. J Mol Biol 197:397–404
Dorn R, Heymann S, Lindigkeit R, Reuter G (1986) Suppressor mutation of position effect variegation inDrosophila melanogaster affecting chromatin properties. Chromosoma 93:398–403
Dunn R, Delaney AD, Gillam IC, Hayashi S, Tener GM, Grigliatti T, Misra V, Spurr MG, Taylor DM, Miller RC Jr (1979) Isolation and characterization of recombinant DNA plasmids carryingDrosophila tRNA genes. Gene 7:197–215
Endow SA, Glover DM (1979) Differential replication of ribosomal gene repeats in polytene nuclei ofDrosophila. Cell 17:597–605
Ephrussi B, Beadle GW (1936) A technique of transplantation forDrosophila. Am Nat 70:218–225
Frankham R (1988) Molecular hypotheses for position-effect variegation: anti-sense transcription and promoter occlusion. J Theor Biol 135:85–107
Gall JG, Pardue ML (1971) Nucleic acid hybridization in cytological preparations. Methods Enzymol 21:470–480
Gerazimova TI, Gvozdev VA, Birstein VJ (1972) Position-effect variegation of Pdg locus of determining 6-phosphogluconate dehydrogenase inDrosophila melanogaster. Dros Inf Ser 48:81
Hartmann-Goldstein IJ (1967) On the relationship between heterochromatinization and variegation inDrosophila, with special reference to temperature-sensitive periods. Genet Res 10:143–159
Hayashi S, Addison WR, Gillam IC, Grigliatti TA, Tener GM (1981) Hybridization of tRNAs ofDrosophila melanogaster to the region of the 5S RNA genes of the polytene chromosomes. Chromosoma 82:385–397
James TC, Elgin SCR (1986) Identification of a nonhistone chromosomal protein associated with heterochromatin inDrosophila melanogaster and its gene. Mol Cell Biol 6:3862–3872
Levis R, Bingham PM, Rubin GM (1982) Physical map of the white locus ofDrosophila melanogaster. Proc Natl Acad Sci USA 79:564–568
Lindsley DL, Grell EH (1968) Genetic variations ofDrosophila melanogaster. Carnegie Inst Wash Publ 627
Marusyk R, Sergeant A (1980) A simple method for dialysis of small-volume samples. Anal Biochem 105:403–404
McGinnis W, Beckendorf SK (1983) Association ofDrosophila transposable element of the roo family with chromosomal deletion breakpoints. Nucleic Acids Res 11:737–751
Moore GD, Procunier JD, Cross DP, Grigliatti TA (1979) Histone gene deficiencies and position effect variegation inDrosophila. Nature 282:312–314
Moore GD, Sinclair DA, Grigliatti TA (1983) Histone gene multiplicity and position-effect variegation inDrosophila melanogaster. Genetics 105:327–344
Mottus R, Reeves R, Grigliatti TA (1980) Butyrate suppression of position-effect variegation inDrosophila melanogaster. Mol Gen Genet 178:465–469
O'Hare K, Levis R, Rubin GM (1983) Transcription of the white locus inDrosophila melanogaster. Proc Natl Acad Sci USA 80:6917–6921
Prokofyeva-Belgovskaya AA (1941) Cytological properties of inert regions and their bearing on the mechanics of mosaicism and chromosome rearrangement. Dros Inf Serv 15:34–35
Reuter G, Wolff I (1981) Isolation of dominant suppressor mutations for position-effect variegation inDrosophila melanogaster. Mol Gen Genet 182:516–519
Reuter G, Werner W, Hoffmann HJ (1982) Mutants affecting position-effect heterochromatinization inDrosophila melanogaster. Chromosoma 85:539–551
Reuter G, Dorn R, Wustmann G, Friede B, Rauh G (1986) Third chromosome suppressor of position-effect variegation loci inDrosophila melanogaster. Mol Gen Genet 202:481–487
Rigby PWJ, Dieckmann M, Rhodes C, Berg P (1977) Labeling deoxyribonucleic acid to high specific activity in vitro by nick translation with DNA polymerase I. J Mol Biol 113:237–251
Roberts DB, Wolfe J, Akam ME (1977) The developmental profiles of two major haemolymph proteins fromDrosophila melanogaster. J Insect Physiol 23:871–878
Rushlow CA, Bender W, Chovnick A (1984) Studies on the mechanism of heterochromatic position effect at the rosy locus ofDrosophila melanogaster. Genetics 108:603–615
Shoup JR (1966) The development of pigment granules in the eyes of wild type and mutantDrosophila melanogaster. J Cell Biol 29:223–249
Sinclair DAR, Mottus RC, Grigliatti TA (1983) Genes which suppress position-effect variegation inDrosophila melanogaster are clustered. Mol Gen Genet 191:326–333
Sinclair DAR, Lloyd YK, Grigliatti TA (1989) Characterization of mutations that enhance position effect variegation inDrosophila melanogaster. Mol Gen Genet 216:328–333
Smith DF, McClelland A, White BN, Addison CF, Glover DM (1981) The molecular cloning of a dispersed set of developmentally regulated genes which encode the major larval serum protein ofD. melanogaster. Cell 23:441–449
Southern EM (1975) Detection of specific sequences among DNA fragments separated by gel electrophoresis. J Mol Biol 98:503–517
Spofford JB (1976) Position-effect variegation inDrosophila. In: Ashburner M, Novitski E (eds) The genetics and biology ofDrosophila, vol 1c. Academic Press, New York, pp 955–1018
Tartof KD, Hobbs C, Jones M (1984) A structural basis for variegating position effects. Cell 37:869–878
Wu C, Bingham PM, Livak KJ, Holmgren R, Elgin SCR (1979) The chromatin structure of specific genes: I. Evidence for higher order domains of defined DNA sequence. Cell 16:797–806
Yoon JS, Richardson RH, Wheeler MR (1973) A technique for improving salivary chromosome preparations. Experientia 29:639–641
Zhimulev IF, Belyaeva ES, Fomina OV, Protopopov MO, Bolshakov VN (1986) Cytogenetic and molecular aspects of position effect variegation inDrosophila melanogaster. I. Morphology and genetic activity of the 2AB region in chromosome rearrangement T(1;2)dorvar7. Chromosoma 94:492–504
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Hayashi, S., Ruddell, A., Sinclair, D. et al. Chromosomal structure is altered by mutations that suppress or enhance position effect variegation. Chromosoma 99, 391–400 (1990). https://doi.org/10.1007/BF01726690
Received:
Revised:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF01726690