title: Cloning and expression of Drosophila HP1 homologs from a mealybug, Planococcus citri.
abstract: The mealybug chromosome cycle is one of the most dramatic examples of genomic imprinting known. In embryos that are to become male the entire paternal chromosome set becomes heterochromatic and inactive at the blastoderm stage, while the maternal set remains active and euchromatic. HP1 is a protein from Drosophila melanogaster, which binds preferentially to heterochromatin on polytene chromosomes and is likely to be a modifier of position effect variegation. This paper describes the isolation and sequencing of two cDNA clones encoding HP1 homologs from the mealybug, Planococcus citri. The protein product of the cDNA clone that was closer to HP1 in sequence was expressed as a fusion protein in Escherichia coli, and polyclonal rat antibodies were raised against it. Immunohistochemistry to mealybug squash preparations showed that this protein was a male-specific nuclear protein, but that it was not specifically associated with the heterochromatic set of chromosomes.
authors.affiliation: Department of Genetics, University of Cambridge, UK.
authors.forename: H
authors.initials: H
authors.lastname: Epstein
authors.forename: T C
authors.initials: TC
authors.lastname: James
authors.forename: P B
authors.initials: PB
authors.lastname: Singh
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D000090266:Chromobox Protein Homolog 5; D002868:Chromosomal Proteins, Non-Histone / Q000096:biosynthesis / Q000235:genetics; D003001:Cloning, Molecular; D004331:Drosophila melanogaster / Q000235:genetics; D005818:Genetic Engineering; D006430:Hemiptera / Q000235:genetics* / Q000254:growth & development; D007301:Insect Hormones / Q000096:biosynthesis / Q000235:genetics* / Q000276:immunology / Q000302:isolation & purification; D019476:Insect Proteins; D008969:Molecular Sequence Data; D005810:Multigene Family / Q000235:genetics; D009687:Nuclear Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000276:immunology / Q000302:isolation & purification; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification; D012689:Sequence Homology, Nucleic Acid; D012727:Sex Characteristics; D014018:Tissue Distribution
chemical_list: D002868:Chromosomal Proteins, Non-Histone; D007301:Insect Hormones; D019476:Insect Proteins; D009687:Nuclear Proteins; D011993:Recombinant Fusion Proteins; D000090266:Chromobox Protein Homolog 5; C075670:pchet1 protein, Planococcus citri; C075671:pchet2 protein, Planococcus citri