Functional domain analysis of human HP1 isoforms in Drosophila.
Three subtypes of HP1, a conserved non-histone chromosomal protein enriched in heterochromatin, have been identified in humans, HP1alpha, beta and gamma. In the present study, we utilized a Drosophila system to characterize human HP1 functions. Over-expression of HP1beta in eye imaginal discs caused abnormally patterned eyes, with reduced numbers of ommatidia, and over-expression of HP1gamma in wing imaginal discs caused abnormal wings, in which L4 veins were gapped. These phenotypes were specific to the HP1 subtypes and appear to reflect suppressed gene expression. To determine the molecular domains of HP1 required for each specific phenotype, we constructed a series of chimeric molecules with HP1beta and HP1gamma. Our data show that the C-terminal chromo shadow domain (CSD) of HP1gamma is necessary for HP1gamma-type phenotype, whereas for the HP1beta-type phenotype both the chromo domain and the CSD are required. These results suggest human HP1 subtypes use different domains to suppress gene expression in Drosophila cells.
Kato
Masaki
M
Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto, Japan.
Kato
Yasuko
Y
Nishida
Miki
M
Hayakawa
Tomohiro
T
Haraguchi
Tokuko
T
Hiraoka
Yasushi
Y
H Inoue
Yoshihiro
Y
Yamaguchi
Masamitsu
M
D000595:Amino Acid Sequence; D000818:Animals; D030801:Animals, Genetically Modified; D000090266:Chromobox Protein Homolog 5; D002868:Chromosomal Proteins, Non-Histone / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002875:Chromosomes / Q000378:metabolism; D004330:Drosophila / Q000235:genetics*; D006570:Heterochromatin / Q000378:metabolism*; D006801:Humans; D008969:Molecular Sequence Data; D020033:Protein Isoforms / Q000737:chemistry / Q000378:metabolism; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid
C000715593:CBX1 protein, human; C000715594:CBX5 protein, human; D002868:Chromosomal Proteins, Non-Histone; D006570:Heterochromatin; D020033:Protein Isoforms; D000090266:Chromobox Protein Homolog 5