Overlapping domains of the heterochromatin-associated protein HP1 mediate nuclear localization and heterochromatin binding.
The Drosophila protein HP1 is a 206 amino acid heterochromatin-associated nonhistone chromosomal protein. Based on the characterization of HP1 to date, there are three properties intrinsic to HP1: nuclear localization, heterochromatin binding, and gene silencing. In this work, we have concentrated on the identification of domains responsible for the nuclear localization and heterochromatin binding properties of HP1. We have expressed a series of beta-galactosidase/HP1 fusion proteins in Drosophila embryos and polytene tissue and have used beta-galactosidase enzymatic activity to identify the subcellular localization of each fusion protein. We have identified two functional domains in HP1: a nuclear localization domain of amino acids 152-206 and a heterochromatin binding domain of amino acids 95-206. Both of these functional domains overlap an evolutionarily conserved COOH-terminal region.
Powers
J A
JA
Edward A. Doisy Department of Biochemistry and Molecular Biology, St. Louis University School of Medicine, Missouri 63104.
Eissenberg
J C
JC
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D005075:Biological Evolution; D002467:Cell Nucleus / Q000378:metabolism* / Q000648:ultrastructure; D000090266:Chromobox Protein Homolog 5; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics* / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D006570:Heterochromatin / Q000378:metabolism* / Q000648:ultrastructure; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009838:Oligodeoxyribonucleotides; D010957:Plasmids; D016133:Polymerase Chain Reaction / Q000379:methods; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D001616:beta-Galactosidase / Q000378:metabolism
D002868:Chromosomal Proteins, Non-Histone; D006570:Heterochromatin; D009838:Oligodeoxyribonucleotides; D011993:Recombinant Fusion Proteins; D000090266:Chromobox Protein Homolog 5; D001616:beta-Galactosidase