Purification and characterization of a multicomponent AP-1.junD complex from T cells. Dependence on a separate cellular factor for enhanced DNA binding activity.
TAP-1 (T-cell AP-1) is a previously identified DNA-binding activity that is rapidly induced in activated T cells in the absence of protein synthesis. This activity has been purified over 2,000-fold from the T-cell line MLA144. Purified TAP-1 is a multicomponent complex composed of 38-kDa and 43-kDa junD polypeptides in association with a separate factor(s), distinct from fos, that partly dissociate from the complex during affinity purification but is required for full TAP-1 DNA-binding activity. When reconstituted with TAP-1, this partly dissociated component strongly enhances the DNA-binding activity of the TAP-1 complex. UV-cross-linking analysis identifies the dissociable component of the TAP-1 complex as a separate class of low molecular mass (23-29-kDa) DNA-binding polypeptide(s). 23-29-kDa polypeptides have been partially purified from nuclear extracts derived from MLA144 that enhance TAP-1 DNA-binding activity over 100-fold and increase its contacts with flanking DNA sequence. These results define TAP-1 as a distinct AP-1.junD-containing complex in T cells whose DNA-binding activity is regulated by the interaction of distinct and separate cellular factor(s).
Gardner
K
K
Laboratory of Pathology, NCI, National Institutes of Health, Bethesda, Maryland 20892.
Moore
T C
TC
Davis-Smyth
T
T
Krutzsch
H
H
Levens
D
D
D000818:Animals; D001483:Base Sequence; D001685:Biological Factors / Q000378:metabolism*; D004247:DNA / Q000378:metabolism*; D006922:Hylobates; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010455:Peptides / Q000378:metabolism; D011485:Protein Binding; D016755:Proto-Oncogene Proteins c-jun / Q000302:isolation & purification* / Q000378:metabolism; D013601:T-Lymphocytes / Q000378:metabolism*; D018808:Transcription Factor AP-1 / Q000302:isolation & purification* / Q000378:metabolism; D014407:Tumor Cells, Cultured; D014466:Ultraviolet Rays
D001685:Biological Factors; D010455:Peptides; D016755:Proto-Oncogene Proteins c-jun; D018808:Transcription Factor AP-1; D004247:DNA