title: Umbrea, a chromo shadow domain protein in Drosophila melanogaster heterochromatin, interacts with Hip, HP1 and HOAP.
abstract: Drosophila melanogaster HP1-interacting protein (Hip) is a partner of heterochromatin protein 1 (HP1) and is involved in transcriptional epigenetic gene silencing and the formation of heterochromatin. Recently, it has been shown that HP1 interacts with the telomere capping factor HP1/ORC (origin recognition complex)-associated protein (HOAP). Telomeres, complexes of DNA and proteins at the end of linear chromosomes, have been recognized to protect chromosome ends from degradation and fusion events. Both proteins are located at telomeres and prevent telomere fusions. Here, we report the identification and characterization of the Hip-interacting protein Umbrea. We found that Umbrea interacts directly with Hip, HP1 and HOAP in vitro. Umbrea, Hip and HP1 are partners in a protein complex in vivo and completely co-localize in the pericentric heterochromatin and at telomeres. Using a Gal4-induced RNA interference system, we found that after depletion of Umbrea in salivary gland polytene chromosomes, they exhibit multiple telomeric fusions. Taken together, these results suggest that Umbrea cooperates with Hip, HP1 and HOAP and plays a functional role in mediating normal telomere behaviour in Drosophila.
authors.affiliation: Institut für Biologie, Freie Universität Berlin, Arnimallee 7, 14195, Berlin, Germany. aschwend@genetik.fu-berlin.de
authors.forename: Christian
authors.initials: C
authors.lastname: Joppich
authors.forename: Sabrina
authors.initials: S
authors.lastname: Scholz
authors.forename: Günter
authors.initials: G
authors.lastname: Korge
authors.forename: Alexander
authors.initials: A
authors.lastname: Schwendemann
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002868:Chromosomal Proteins, Non-Histone / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D002875:Chromosomes / Q000378:metabolism / Q000648:ultrastructure; D029721:Drosophila Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000235:genetics / Q000378:metabolism*; D006570:Heterochromatin / Q000378:metabolism*; D015151:Immunoblotting; D008957:Models, Genetic; D008969:Molecular Sequence Data; D009154:Mutation; D016615:Telomere / Q000378:metabolism
chemical_list: D002868:Chromosomal Proteins, Non-Histone; D029721:Drosophila Proteins; C539839:HP6 protein, Drosophila; D006570:Heterochromatin; C539840:Hip protein, Drosophila; C471206:cav protein, Drosophila; C452193:heterochromatin protein 1, Drosophila