Interaction of heterochromatin protein 2 with HP1 defines a novel HP1-binding domain.
Heterochromatin Protein 2 (HP2) is a nonhistone chromosomal protein from Drosophila melanogaster localized principally in the pericentric heterochromatin, telomeres, and fourth chromosome, all regions associated with HP1. Mutations in HP2 can suppress position effect variegation, indicating a role in gene silencing and heterochromatin formation [Shaffer, C. D. et al. (2002) Proc. Natl. Acad. Sci.U.S.A. 99, 14332-14337]. In vitro coimmunoprecipitation experiments with various peptides from HP2 have identified a single HP1-binding domain. Conserved domains in HP2, including those within the HP1-binding region, have been identified by recovering and sequencing Su(var)2-HP2 from D. willistoni and D. virilis, as well as examining available sequence data from D. pseudoobscura. A PxVxL motif, shown to be an HP1-binding domain in many HP1-interacting proteins, is observed but is not well-conserved in location and sequence and does not mediate HP2 binding to HP1. The sole HP1-binding domain is composed of two conserved regions of 12 and 16 amino acids separated by 19 amino acids. Site-directed mutagenesis within the two conserved regions has shown that the 16 amino acid domain is critical for HP1 binding. This constitutes a novel domain for HP1 interaction, providing a critical link for heterochromatin formation in Drosophila.
Stephens
Gena E
GE
Department of Biology, Washington University, CB-1229, St. Louis, Missouri 63130, USA. gebloth@artsci.wustl.edu
Slawson
Elizabeth E
EE
Craig
Carolyn A
CA
Elgin
Sarah C R
SC
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D015153:Blotting, Western; D002467:Cell Nucleus / Q000378:metabolism; D002868:Chromosomal Proteins, Non-Histone / Q000737:chemistry* / Q000378:metabolism; D018076:DNA, Complementary / Q000378:metabolism; D004330:Drosophila; D029721:Drosophila Proteins / Q000737:chemistry* / Q000378:metabolism; D019143:Evolution, Molecular; D006570:Heterochromatin / Q000737:chemistry* / Q000378:metabolism; D047468:Immunoprecipitation; D008856:Microscopy, Fluorescence; D008957:Models, Genetic; D008969:Molecular Sequence Data; D009154:Mutation; D010455:Peptides / Q000737:chemistry; D010957:Plasmids / Q000378:metabolism; D011485:Protein Binding; D020033:Protein Isoforms; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity
D002868:Chromosomal Proteins, Non-Histone; D018076:DNA, Complementary; D029721:Drosophila Proteins; D006570:Heterochromatin; D010455:Peptides; D020033:Protein Isoforms; C452193:heterochromatin protein 1, Drosophila; C506595:heterochromatin protein 2, Drosophila