Repression of the IgH enhancer in teratocarcinoma cells associated with a novel octamer factor.
Embryonal carcinoma (EC) cell lines are models for early cells in mouse embryogenesis. A 300-base pair fragment of the heavy chain enhancer was inactive in F9 EC cells, unlike in other nonlymphoid cells where it has significant activity. Alterations of the octamer motif increased enhancer activity. Nuclear extracts from F9 cells contained an octamer binding protein (NF-A3) that was unique to EC cells; the amount of NF-A3 decreased upon differentiation. It is proposed that NF-A3 represses specific regulatory sequences that contain the octamer motif. Thus, the same DNA sequence mediates either negative or positive transcriptional effects, depending on the cell type.
Lenardo
M J
MJ
Whitehead Institute for Biomedical Research, Cambridge, MA 02142.
Staudt
L
L
Robbins
P
P
Kuang
A
A
Mulligan
R C
RC
Baltimore
D
D
D000818:Animals; D003994:Bucladesine / Q000494:pharmacology; D002454:Cell Differentiation; D004247:DNA / Q000378:metabolism; D054278:Embryonal Carcinoma Stem Cells; D004742:Enhancer Elements, Genetic; D007143:Immunoglobulin Heavy Chains / Q000235:genetics*; D046911:Macromolecular Substances; D051379:Mice; D009154:Mutation; D014411:Neoplastic Stem Cells / Q000378:metabolism*; D012333:RNA, Messenger / Q000096:biosynthesis; D012045:Regulatory Sequences, Nucleic Acid; D012097:Repressor Proteins / Q000235:genetics; D014158:Transcription, Genetic; D014162:Transfection; D014212:Tretinoin / Q000494:pharmacology; D014407:Tumor Cells, Cultured
D007143:Immunoglobulin Heavy Chains; D046911:Macromolecular Substances; D012333:RNA, Messenger; D012097:Repressor Proteins; D014212:Tretinoin; D003994:Bucladesine; D004247:DNA