NF-kappaB elements associated with the Stat6 site in the germline gamma1 immunoglobulin promoter are not necessary for the transcriptional response to CD40 ligand.
Both germline transcription and switch recombination of heavy chain genes are likely to be regulated by cis elements binding transcription factors in the promoter regions of germline immunoglobulin genes. To identify cis-acting elements important in germline transcription of the murine gamma1 heavy chain gene, we have used a transgenic approach. Seventeen kb gamma1 immunoglobulin transgenes with mutations in three NF-kappaB sites in the gamma1 proximal promoter, a putative CD40 response element, are expressed well. Compared to wild-type transgenes, there is no deficiency in the expression of the transgenes with mutations of the three NF-kappaB sites after induction of splenic B cells with IL-4 alone, CD40L, or CD40L + IL-4. There may be a small reduction in the response of these mutant transgenes after induction with LPS + IL-4. We also prepared transgenes that were truncated at -150 (rather than -2100) and therefore included the wild-type Stat6 binding site at -123 and the three wild-type NF-kappaB sites. Nevertheless, gamma1 germline transcripts were not expressed from these transgenes. We conclude that the three proximal NF-kappaB sites are dispensable for expression of gamma1 germline transcripts under most conditions. However, cis-acting elements distal to -150 must be critical to this transcription.
Berton
Michael T
MT
Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229-3900, USA. berton@uthscsa.edu
Linehan
Leslie A
LA
Wick
Kerilyn R
KR
Dunnick
Wesley A
WA
D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology / Q000378:metabolism; D023201:CD40 Ligand / Q000235:genetics / Q000494:pharmacology / Q000502:physiology*; D018628:Gene Dosage; D005786:Gene Expression Regulation; D005854:Germ Cells / Q000378:metabolism; D007142:Immunoglobulin gamma-Chains / Q000235:genetics*; D015847:Interleukin-4 / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000494:pharmacology; D051379:Mice; D008822:Mice, Transgenic; D009154:Mutation / Q000235:genetics; D016328:NF-kappa B / Q000235:genetics / Q000502:physiology*; D011401:Promoter Regions, Genetic / Q000235:genetics / Q000502:physiology; D020218:Response Elements / Q000235:genetics / Q000502:physiology*; D050800:STAT6 Transcription Factor; D015534:Trans-Activators / Q000235:genetics; D014158:Transcription, Genetic
D007142:Immunoglobulin gamma-Chains; D008070:Lipopolysaccharides; D016328:NF-kappa B; D050800:STAT6 Transcription Factor; C494100:Stat6 protein, mouse; D015534:Trans-Activators; D023201:CD40 Ligand; D015847:Interleukin-4