Cross-linking of surface Ig receptors on murine B lymphocytes stimulates the expression of nuclear tetradecanoyl phorbol acetate-response element-binding proteins.
Cross-linking of sIg on primary B lymphocytes leads to increased nuclear DNA-binding activity specific for the tetradecanoyl phorbol acetate-response element (TRE), as judged by gel mobility shift assays. Stimulation of B cells to enter S phase of the cell cycle by treatment with the combination of phorbol ester plus calcium ionophore also stimulated nuclear TRE-binding activity within 2 h, with maximal expression at 4 h; however, phorbol ester and calcium ionophore were not as effective in stimulating binding activity when examined separately. Stimulated nuclear expression of TRE-binding activity appears to require protein synthesis. Fos- and Jun/AP-1-related proteins participate directly in the identified nucleoprotein complex, as shown by the ability of c-fos- and c-jun-specific antisera to either alter or completely abolish electrophoretic migration of the complex in native gels. Further, UV photo-cross-linking studies identified two major TRE-binding protein species, whose sizes correspond to TRE-binding proteins derived from HeLa cell nuclear extracts. The results suggest that in primary B cells nuclear TRE-binding activity represents a "downstream" signaling event that occurs subsequent to changes in protein kinase C activity and intracellular Ca2+ but that can be triggered "physiologically" through sIg.
Chiles
T C
TC
Evans Memorial Department of Clinical Research, Boston University Medical Center, MA 02118.
Liu
J L
JL
Rothstein
T L
TL
D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology*; D002467:Cell Nucleus / Q000737:chemistry; D004268:DNA-Binding Proteins / Q000032:analysis / Q000096:biosynthesis*; D005786:Gene Expression Regulation / Q000187:drug effects; D015759:Ionomycin / Q000494:pharmacology; D046911:Macromolecular Substances; D051379:Mice; D008807:Mice, Inbred BALB C; D011518:Proto-Oncogene Proteins / Q000032:analysis; D016760:Proto-Oncogene Proteins c-fos; D016755:Proto-Oncogene Proteins c-jun; D011947:Receptors, Antigen, B-Cell / Q000502:physiology*; D012045:Regulatory Sequences, Nucleic Acid / Q000502:physiology; D016196:S Phase / Q000502:physiology; D015398:Signal Transduction / Q000276:immunology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*; D014157:Transcription Factors / Q000032:analysis; D014466:Ultraviolet Rays
D004268:DNA-Binding Proteins; D046911:Macromolecular Substances; D011518:Proto-Oncogene Proteins; D016760:Proto-Oncogene Proteins c-fos; D016755:Proto-Oncogene Proteins c-jun; D011947:Receptors, Antigen, B-Cell; D014157:Transcription Factors; D015759:Ionomycin; D013755:Tetradecanoylphorbol Acetate