Interaction of a nuclear protein with a palindromic sequence of the mouse immunoglobulin lambda 2-chain gene promoter is important for its transcription.
By using a gel mobility retardation assay, we detected the formation of three major complexes from the binding of nuclear proteins to the promoter of the immunoglobulin lambda 2-chain gene. Two of the complexes were generated by the presence of an unidentified nuclear factor(s) called herein NF-lambda 2. Although the sequences between lambda 2- and lambda 1-chain gene promoters are very similar, the lambda 1-chain promoter did not compete for the binding of NF-lambda 2 efficiently. The binding site of NF-lambda 2 was localized by DNase I footprinting to a 14-bp region which is about 30 bp upstream of the immunoglobulin octamer motif. This region, referred to as the NF-lambda 2 motif, is within an 18-bp region of twofold rotational symmetry. Experiments with oligomers containing either the NF-lambda 2 or the octamer motifs as competitors for binding and DNase I footprinting, showed that the third complex is the product of the simultaneous binding of an octamer-binding protein and NF-lambda 2. Changing the sequence of the NF-lambda 2 motif to that of the lambda 1-chain counterpart abolished the binding ability of NF-lambda 2. Concomitantly, the level of chloramphenicol acetyltransferase expression driven by the mutated lambda 2 promoter decreased by two- to fivefold when compared with that of the wild-type promoter. It is therefore concluded that the interaction of NF-lambda 2 with the NF-lambda 2 motif stimulates transcription of the lambda 2-chain gene.
Chang
L A
LA
Department of Medical Genetics, University of Toronto, Ontario, Canada.
Murialdo
H
H
D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D005786:Gene Expression Regulation; D005803:Genes, Immunoglobulin; D007146:Immunoglobulin lambda-Chains / Q000235:genetics*; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D015345:Oligonucleotide Probes; D010954:Plasmacytoma; D010957:Plasmids; D011401:Promoter Regions, Genetic; D015183:Restriction Mapping; D016385:TATA Box; D014158:Transcription, Genetic
D007146:Immunoglobulin lambda-Chains; D009687:Nuclear Proteins; D015345:Oligonucleotide Probes