TY - JOUR
T1 - Remodelling of the S3 PA700 proteasome activator gene chromatin structure during thymocyte differentiation
AU - Antoniou, Antony N
AU - Moore, Nel
AU - Dyson, Julian P.
PY - 2002/7
Y1 - 2002/7
N2 - The proteasome is the major cytosolic protease, composed of a 20S catalytic core that associates with either the 19S (PA700) activator or the 11S (PA28) regulator complex. The 19S complex is thought to promote protein substrate unfolding and subsequent degradation, but precise functions for the individual subunits remain undefined. The chromatin structure and regulation of the S3 (P91A) subunit of the 19S activator was examined as a novel approach towards understanding its role in the complex. DNase I hypersensitivity (HS) analysis of S3 chromatin revealed a ubiquitous DNase I HS site mapping to the promoter region. Examination of the S3 chromatin structure in thymocytes, a dynamic population that undergo substantial proliferation, apoptosis, and differentiation, revealed an additional DNase I HS site mapping to the sixth intron of the genomic sequence. This second site was demonstrated to be associated with CD4(+)CD8(+) double-positive (DP) but not CD4(+) single-positive (SP) thymoma cell lines, and may correlate with a downregulation of S3 message. When a DP thymic cell line was induced to differentiate through retroviral transduction with Notch-1, the second DNase I HS site was dramatically diminished, illustrating that S3 chromatin is developmentally regulated during thymocyte positive selection.
AB - The proteasome is the major cytosolic protease, composed of a 20S catalytic core that associates with either the 19S (PA700) activator or the 11S (PA28) regulator complex. The 19S complex is thought to promote protein substrate unfolding and subsequent degradation, but precise functions for the individual subunits remain undefined. The chromatin structure and regulation of the S3 (P91A) subunit of the 19S activator was examined as a novel approach towards understanding its role in the complex. DNase I hypersensitivity (HS) analysis of S3 chromatin revealed a ubiquitous DNase I HS site mapping to the promoter region. Examination of the S3 chromatin structure in thymocytes, a dynamic population that undergo substantial proliferation, apoptosis, and differentiation, revealed an additional DNase I HS site mapping to the sixth intron of the genomic sequence. This second site was demonstrated to be associated with CD4(+)CD8(+) double-positive (DP) but not CD4(+) single-positive (SP) thymoma cell lines, and may correlate with a downregulation of S3 message. When a DP thymic cell line was induced to differentiate through retroviral transduction with Notch-1, the second DNase I HS site was dramatically diminished, illustrating that S3 chromatin is developmentally regulated during thymocyte positive selection.
KW - Animals
KW - Cell Differentiation
KW - Cell Line
KW - Chromatin/ultrastructure
KW - Cysteine Endopeptidases/chemistry
KW - Deoxyribonuclease I/chemistry
KW - Down-Regulation
KW - Female
KW - Membrane Proteins/metabolism
KW - Mice
KW - Mice, Inbred DBA
KW - Multienzyme Complexes/chemistry
KW - Proteasome Endopeptidase Complex
KW - Protein Biosynthesis
KW - Protein Subunits
KW - Proteins/genetics
KW - Receptor, Notch1
KW - Receptors, Cell Surface
KW - T-Lymphocytes/enzymology
KW - Thymus Gland/cytology
KW - Tissue Distribution
KW - Transcription Factors
KW - Tumor Cells, Cultured
U2 - 10.1007/s00251-002-0475-3
DO - 10.1007/s00251-002-0475-3
M3 - Article
C2 - 12136337
VL - 54
SP - 260
EP - 267
JO - Immunogenetics
JF - Immunogenetics
SN - 0093-7711
IS - 4
ER -