Identification of USF as the ubiquitous murine factor that binds to and stimulates transcription from the immunoglobulin lambda 2-chain promoter.
To study the specificity and identity of NF-lambda 2, a ubiquitous murine nuclear factor that interacts specifically with the promoter of the lambda 2-chain gene and stimulates its transcription, competition experiments were carried out using DNA fragments from various immunoglobulin regulatory elements. The results showed that a fragment containing the H-chain enhancer competed efficiently for the binding of NF-lambda 2. Dissection of the H-chain enhancer revealed that the microE3 motif contributed the competing ability. Additionally, a regulatory region found in the adenovirus major late promoter, which interacts with the human general transcription factor USF, competed very efficiently for binding to NF-lambda 2. This region contains a sequence, CACGTGAC, which is identical to a region within the NF-lambda 2 motif. The pattern of complexes formation using oligonucleotide probes corresponding to the NF-lambda 2 and USF motifs were identical, and they both differed from that displayed by the E3 probes. Antisera against different domains of USF also react specifically with NF-lambda 2 showing that this factor is antigenically related, if not identical, to USF. Furthermore, the activity of the lambda 2 promoter in an in vitro transcription assay was significantly reduced when the nuclear extract used was USF-depleted. Addition of exogenous USF to this extract restored the transcription activity. Therefore, we conclude that NF-lambda 2 is the murine homologue of USF.
Chang
L A
LA
Department of Molecular and Medical Genetics, University of Toronto, Ontario, Canada.
Smith
T
T
Pognonec
P
P
Roeder
R G
RG
Murialdo
H
H
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D004268:DNA-Binding Proteins; D005786:Gene Expression Regulation / Q000235:genetics*; D005803:Genes, Immunoglobulin; D007146:Immunoglobulin lambda-Chains / Q000235:genetics*; D051379:Mice; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic / Q000235:genetics*; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D014407:Tumor Cells, Cultured; D051720:Upstream Stimulatory Factors
D004268:DNA-Binding Proteins; D007146:Immunoglobulin lambda-Chains; D014157:Transcription Factors; D051720:Upstream Stimulatory Factors; C497183:Usf1 protein, mouse