Chromosoma

, Volume 106, Issue 1, pp 11–19 | Cite as

Heterochromatin protein HP1Hsβ(p25β) and its localization with centromeres in mitosis

  • Kiyoshi Furuta
  • Edward K. L. Chan
  • Kendo Kiyosawa
  • Georg Reimer
  • Christoph Luderschmidt
  • Eng M. Tan

Abstract.

Some autoimmune sera containing anticentromere autoantibodies also recognize a doublet of Mr 23 000 (p23) and 25 000 (p25) in addition to CENP (centromere protein)-A (Mr 19 000), -B (Mr 80 000), and -C (Mr 140 000). A p25 antigen (HP1Hsα) has been shown to be a human homolog of Drosophila HP1 (heterochromatin protein 1). We have isolated a cDNA clone encoding another form of p25 (HP1Hsβor p25β) from a λZap HepG2 library using human autoimmune serum. The deduced amino acid sequence of the clone contained a conserved chromodomain (chromatin modifier domain) in the N-terminal region and a heterochromatin binding domain in the C-terminal region. In immunofluorescence experiments, only affinity purified antibodies reactive with the C-terminal (amino acids 70–185) domain showed nucleoplasmic and heterochromatin staining, whereas N-terminal (amino acids 1–115) specific antibodies were nonreactive. In metaphase chromosome spreads, the C-terminal domain antibody was also localized to the centromeric regions of chromosomes. Association with centromeres was most prominent at anaphase and changed to a more generalized association with whole chromosomes in telophase. The cooccurrence of autoantibodies to centromere proteins and HP1 in certain autoimmune diseases might be a reflection of coordinated immune responses to these closely associated sets of proteins.

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Copyright information

© Springer-Verlag Berlin Heidelberg 1997

Authors and Affiliations

  • Kiyoshi Furuta
    • 1
  • Edward K. L. Chan
    • 1
  • Kendo Kiyosawa
    • 2
  • Georg Reimer
    • 3
  • Christoph Luderschmidt
    • 4
  • Eng M. Tan
    • 1
  1. 1.Department of Molecular and Experimental Medicine, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USAUS
  2. 2.Second Department of Internal Medicine, Shinshu University School of Medicine, Matsumoto-shi 390, JapanJP
  3. 3.Department of Dermatology, University of Erlangen, Erlangen, GermanyDE
  4. 4.Department of Dermatology, University of Munich, Munich, GermanyDE

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