Heterochromatic deposition of centromeric histone H3-like proteins.
Centromeres of most organisms are embedded within constitutive heterochromatin, the condensed regions of chromosomes that account for a large fraction of complex genomes. The functional significance of this centromere-heterochromatin relationship, if any, is unknown. One possibility is that heterochromatin provides a suitable environment for assembly of centromere components, such as special centromeric nucleosomes that contain distinctive histone H3-like proteins. We describe a Drosophila H3-like protein, Cid (for centromere identifier) that localizes exclusively to fly centromeres. When the cid upstream region drives expression of H3 and H2B histone-green fluorescent protein fusion genes in Drosophila cells, euchromatin-specific deposition results. Remarkably, when the cid upstream region drives expression of yeast, worm, and human centromeric histone-green fluorescent protein fusion proteins, localization is preferentially within Drosophila pericentric heterochromatin. Heterochromatin-specific localization also was seen for yeast and worm centromeric proteins constitutively expressed in human cells. Preferential localization to heterochromatin in heterologous systems is unexpected if centromere-specific or site-specific factors determine H3-like protein localization to centromeres. Rather, the heterochromatic state itself may help localize centromeric components.
Henikoff
S
S
Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, Seattle, WA 98109-1024, USA. steveh@fhcrc.org
Ahmad
K
K
Platero
J S
JS
van Steensel
B
B
D000595:Amino Acid Sequence; D000818:Animals; D001324:Autoantigens; D002460:Cell Line; D002503:Centromere / Q000235:genetics*; D000076247:Centromere Protein A; D002843:Chromatin / Q000235:genetics; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics; D002874:Chromosome Mapping; D020732:Cytogenetic Analysis; D004268:DNA-Binding Proteins / Q000235:genetics; D004331:Drosophila melanogaster / Q000166:cytology / Q000235:genetics; D022041:Euchromatin; D005656:Fungal Proteins / Q000235:genetics; D049452:Green Fluorescent Proteins; D006367:HeLa Cells; D015801:Helminth Proteins / Q000235:genetics; D006570:Heterochromatin / Q000235:genetics*; D006657:Histones / Q000235:genetics*; D006801:Humans; D019476:Insect Proteins / Q000235:genetics; D008164:Luminescent Proteins / Q000235:genetics; D008969:Molecular Sequence Data; D010802:Phylogeny; D011401:Promoter Regions, Genetic; D011993:Recombinant Fusion Proteins / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014162:Transfection
D001324:Autoantigens; C092746:CSE4 protein, S cerevisiae; D000076247:Centromere Protein A; D002843:Chromatin; D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; D022041:Euchromatin; D005656:Fungal Proteins; D015801:Helminth Proteins; D006570:Heterochromatin; D006657:Histones; D019476:Insect Proteins; D008164:Luminescent Proteins; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; D049452:Green Fluorescent Proteins