Purification and properties of LR1, an inducible DNA binding protein from mammalian B lymphocytes.
LR1 is a lipopolysaccharide-inducible B cell-specific DNA binding activity, with sites in the immunoglobulin heavy chain enhancer and switch regions. We describe the purification of this 106-kDa protein from nuclear extracts of PD31 murine pre-B cells, using three chromatographic steps. The DNA binding activity of LR1 is dependent upon phosphorylation, and we show that LR1 is post-translationally modified by N-acetylglucosamine addition. The importance of regulatory modification to LR1 DNA binding activity is apparent from the chromatographic pattern on the anion exchange resin Mono Q: while the LR1 polypeptide elutes over a broad salt range from the column, DNA binding activity is confined to a narrow peak eluting at the highest salt.
Williams
M
M
Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, Connecticut 06510.
Hanakahi
L A
LA
Maizels
N
N
D000117:Acetylglucosamine / Q000378:metabolism; D000818:Animals; D001402:B-Lymphocytes / Q000378:metabolism*; D001483:Base Sequence; D002460:Cell Line; D002846:Chromatography, Affinity; D002850:Chromatography, Gel; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D006868:Hydrolysis; D051379:Mice; D008969:Molecular Sequence Data; D008970:Molecular Weight; D011499:Protein Processing, Post-Translational; D014157:Transcription Factors / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism
D004268:DNA-Binding Proteins; C087378:LR1 protein, mouse; D014157:Transcription Factors; D004247:DNA; D000117:Acetylglucosamine