Biochemical characterization of the NF-Y transcription factor complex during B lymphocyte development.
The transcription factor, NF-Y, plays a critical role in tissue-specific major histocompatibility complex class II gene transcription. In this report the biochemical properties of the heterotrimeric NF-Y complex have been characterized during stage-specific B-cell development, and in several class II- mutant B-cell lines, which represent distinct bare lymphocyte syndrome class II genetic complementation groups. The NF-Y complex derived from class II+ mature B-cells bound with high affinity to anion exchangers, and eluted as an intact trimeric complex, whereas, NF-Y derived from class II- plasma B-cells, and from bare lymphocyte syndrome group II cell lines, RJ2.2.5 and RM3, dissociated into discrete NF-YA and NF-YB:C subunit fractions. Recombination of the MPC11 plasma B-cell derived NF-Y A:B:C complex with the low molecular mass protein fraction, NF-Y-associated factors (YAFs), derived from mature A20 B-cell nuclei, conferred high affinity anion exchange binding to NF-Y as an intact trimeric complex. Recombination of the native NF-YA:B:C complex with the transcriptional cofactor, PC4, likewise conferred high affinity NF-Y binding to anion exchangers, and stabilized NF-Y interaction with CCAAT-box DNA motifs in vitro. Interaction between PC4 and NF-Y was mapped to the C-terminal region of PC4, and the subunit interaction subdomain of the highly conserved DNA binding-subunit interaction domain (DBD) of NF-YA. These results suggest that in class II+ mature B-cells NF-Y is associated with the protein cofactor, PC4, which may play an important role in NF-Y-mediated transcriptional control of class II genes.
Currie
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Laboratory of Gene Regulation, The Wheeler Institute for Biomedical Research, Huntington, New York 11743, USA.
D001402:B-Lymphocytes / Q000378:metabolism*; D022762:CCAAT-Enhancer-Binding Proteins; D002460:Cell Line; D002852:Chromatography, Ion Exchange; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D005802:Genes, MHC Class II / Q000235:genetics; D006801:Humans; D017874:Immediate-Early Proteins; D046911:Macromolecular Substances; D008565:Membrane Proteins; D011487:Protein Conformation; D011995:Recombination, Genetic; D012097:Repressor Proteins; D013329:Structure-Activity Relationship; D015534:Trans-Activators / Q000378:metabolism; D014157:Transcription Factors / Q000737:chemistry / Q000378:metabolism*; D014158:Transcription, Genetic; D014462:Ultrafiltration
D022762:CCAAT-Enhancer-Binding Proteins; D004268:DNA-Binding Proteins; C490043:IFRD2 protein, human; D017874:Immediate-Early Proteins; D046911:Macromolecular Substances; D008565:Membrane Proteins; D012097:Repressor Proteins; D015534:Trans-Activators; D014157:Transcription Factors; D004247:DNA