The human polycomb group complex associates with pericentromeric heterochromatin to form a novel nuclear domain
Author(s)
Type
Journal Article
Abstract
The Polycomb group (PcG) complex is a chromatin-associated multiprotein complex, involved in the stable repression of homeotic gene activity in Drosophila. Recently, a mammalian PcG complex has been identified with several PcG proteins implicated in the regulation of Hox gene expression. Although the mammalian PcG complex appears analogous to the complex in Drosophila, the molecular mechanisms and functions for the mammalian PcG complex remain unknown. Here we describe a detailed characterization of the human PcG complex in terms of cellular localization and chromosomal association. By using antibodies that specifically recognize three human PcG proteins— RING1, BMI1, and hPc2—we demonstrate in a number of human cell lines that the PcG complex forms a unique discrete nuclear structure that we term PcG bodies. PcG bodies are prominent novel nuclear structures with the larger PcG foci generally localized near the centromeres, as visualized with a kinetochore antibody marker. In both normal fetal and adult fibroblasts, PcG bodies are not randomly dispersed, but appear clustered into defined areas within the nucleus. We show in three different human cell lines that the PcG complex can tightly associate with large pericentromeric heterochromatin regions (1q12) on chromosome 1, and with related pericentromeric sequences on different chromosomes, providing evidence for a mammalian PcG–heterochromatin association. Furthermore, these heterochromatin-bound PcG complexes remain stably associated throughout mitosis, thereby allowing the potential inheritance of the PcG complex through successive cell divisions. We discuss these results in terms of the known function of the PcG complex as a transcriptional repression complex.
Date Issued
1998-08-24
Date Acceptance
1998-06-15
Citation
Journal of Cell Biology, 1998, 142 (4), pp.887-898
ISSN
0021-9525
Publisher
Rockefeller University Press
Start Page
887
End Page
898
Journal / Book Title
Journal of Cell Biology
Volume
142
Issue
4
Copyright Statement
© 1998 Rockefeller University Press.
Identifier
http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000075619400001&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
Subjects
Science & Technology
Life Sciences & Biomedicine
Cell Biology
polycomb-group
RING finger protein
centromere
heterochromatin
repression
DROSOPHILA BITHORAX COMPLEX
CENTROMERIC HETEROCHROMATIN
TRANSCRIPTIONAL REPRESSOR
PROTEIN COMPLEX
GENE-EXPRESSION
GAGA-FACTOR
CELL-CYCLE
CHROMATIN
IDENTIFICATION
CONSTITUENTS
Publication Status
Published
Date Publish Online
1998-08-24