The heterochromatin-associated protein HP-1 is an essential protein in Drosophila with dosage-dependent effects on position-effect variegation - PubMed (original) (raw)

The heterochromatin-associated protein HP-1 is an essential protein in Drosophila with dosage-dependent effects on position-effect variegation

J C Eissenberg et al. Genetics. 1992 Jun.

Abstract

Chromosome rearrangements which place euchromatic genes adjacent to a heterochromatic breakpoint frequently result in gene repression (position-effect variegation). This repression is thought to reflect the spreading of a heterochromatic structure into neighboring euchromatin. Two allelic dominant suppressors of position-effect variegation were found to contain mutations within the gene encoding the heterochromatin-specific chromosomal protein HP-1. The site of mutation for each allele is given: one converts Lys169 into a nonsense (ochre) codon, while the other is a frameshift after Ser10. In flies heterozygous for one of the mutant alleles (Su(var)2-504), a truncated HP-1 protein was detectable by Western blot analysis. An HP-1 minigene, consisting of HP-1 cDNA under the control of an Hsp70 heat-inducible promoter, was transduced into flies by P element-mediated germ line transformation. Heat-shock driven expression of this minigene results in elevated HP-1 protein level and enhancement of position-effect variegation. Levels of variegating gene expression thus appear to depend upon the level of expression of a heterochromatin-specific protein. The implications of these observations for mechanism of heterochromatic position effects and heterochromatin function are discussed.

PubMed Disclaimer

Similar articles

Cited by

References

    1. Proc Natl Acad Sci U S A. 1977 Dec;74(12):5463-7 - PubMed
    1. Proc Natl Acad Sci U S A. 1979 Aug;76(8):3683-7 - PubMed
    1. Genetics. 1977 Jul;86(3):567-82 - PubMed
    1. Proc Natl Acad Sci U S A. 1991 Jan 1;88(1):263-7 - PubMed
    1. Trends Genet. 1990 Dec;6(12):416-21 - PubMed

Publication types

MeSH terms

Substances

LinkOut - more resources