Identification of a protein that interacts with the nuclear factor-1 (NF-1) binding site in cells that do not express NF-1: comparison to NF-1, cellular distribution, and effect on transcription.
We examined expression of nuclear factor-1 (NF-1) in different cell lines. Expression was low or undetectable in T and B lymphocyte cell lines, whereas fibroblasts and other adherent cell lines generally had a relatively high level of NF-1 mRNA. In cell lines that did not express NF-1, gel retardation assays, nevertheless, indicated complexes between a protein or proteins and the NF-1 site. These complexes were less abundant than those formed with NF-1, they migrated more slowly, and they appeared as single species instead of the multiple species observed with NF-1. NF-1 site-binding proteins were compared in the fibrosarcoma cell line HT-1080 (expressed the highest level of NF-1 in our study) and the B cell line Raji (does not express NF-1). UV-crosslinking studies indicated that the NF-1 site-binding proteins in both cell lines were similar in size. Proteolytic clipping band shift assays suggested that the Raji protein and NF-1 share structural similarity in their DNA binding domains, but are distinct proteins. The NF-1 site mediated transcriptional stimulation in cell lines where NF-1 is expressed; however, this element did not affect transcription in cell lines that do not express NF-1, suggesting that the NF-1 site-binding protein in these cells is functionally distinct from NF-1.
McQuillan
J J
JJ
Department of Internal Medicine and Cell Biology, Washington University School of Medicine, St Louis, MO 63110.
Rosen
G D
GD
Birkenmeier
T M
TM
Dean
D C
DC
D016475:3T3 Cells; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D015152:Blotting, Northern; D022762:CCAAT-Enhancer-Binding Proteins; D002460:Cell Line; D002918:Chymotrypsin; D006224:Cricetinae; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism* / Q000528:radiation effects; D005786:Gene Expression Regulation; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D051839:NFI Transcription Factors; D009687:Nuclear Proteins; D012333:RNA, Messenger / Q000378:metabolism; D014157:Transcription Factors; D014158:Transcription, Genetic; D014357:Trypsin; D014466:Ultraviolet Rays; D051840:Y-Box-Binding Protein 1
D022762:CCAAT-Enhancer-Binding Proteins; D004268:DNA-Binding Proteins; D051839:NFI Transcription Factors; D009687:Nuclear Proteins; D012333:RNA, Messenger; D014157:Transcription Factors; D051840:Y-Box-Binding Protein 1; C070856:YBX1 protein, human; D004247:DNA; D002918:Chymotrypsin; D014357:Trypsin