Regulation of Mouse 4-1BB Expression: Multiple Promoter Usages and a Splice Variant

Abstract

The expression of 4-1BB has been known to be dependent on T cell activation. Recent studies have, however, revealed that 4-1BB expression is not restricted to T cells. We sought to determine the molecular basis for the differential gene expression. Here we report the expression pattern of two mouse 4-1BB transcripts, type I and type II. Whereas the type I transcript was specifically expressed on immune organ as previously reported, the type II transcript was ubiquitously expressed in tissues and various cell lines. However, both type I and type II transcript were highly induced on activated T cells. Primer extension assay of the two 4-1BB transcripts suggested that mouse 4-1BB had more than two transcripts. Using luciferase assay we have identified three promoter regions (PI, PII and PIII), which located on upstream region of second exon 1, first exon 1, and exon 2, respectively. In particular, the type I transcript was preferentially induced when naïve T cells are stimulated by anti-CD3 monoclonal antibody (mAb) since NF-κB specifically binds to the putative NF-κB element of PI. We have also shown that a splice variant, in which the transmembrane domain was deleted, could inhibit 4-1BB signaling. The splicing variant was highly induced by TCR stimulation. Our results reveal 4-1BB also has a negative regulation system through soluble 4-1BB produced from a splice variant induced under activation conditions.

Identification of Alternative Transcripts Encoding the Essential Murine Gammaherpesvirus Lytic Transactivator RTA

“…Based on the current analyses, MHV68 RTA expression can be driven from four distinct promoters, and these promoters drive expression of 5 different spliced gene 50 transcripts. The identification of multiple promoters driving expression of a single gene is not a novel concept; there are many human and viral genes whose expression has been shown to be regulated by multiple promoters (38)(39)(40)(41)(42). For example, EBV has been shown to use differential splicing and from 2 distinct promoters in the generation of the transcripts encoding the six EBNA gene products (43)(44)(45)(46)(47).…”

Several Cis-regulatory Elements Control mRNA Stability, Translation Efficiency, and Expression Pattern of Prrxl1 (Paired Related Homeobox Protein-like 1)

“…The first-strand cDNA synthesis was prepared at 42°C during 1 h from 1 g of total RNA using 200 units of transcriptase enzyme (Bioline) and 500 ng of oligo(dT) [12][13][14][15][16][17][18] (Bioline). To assess for potential contaminants, a control containing all reagents except the reverse transcriptase enzyme was included for each sample.…”

“…Modulation of gene expression through alternative promoter usage is now widely accepted following evidence gathered in the past years (12,13). According to Baek et al (14), about 40 -50% of human and mouse genes contain alternative promoters, a condition that seems to be required to initiate transcription in a tissue-specific manner (15)(16)(17). The use of multiple promoters, each one controlling at least one transcription start site (TSS), usually originates different 5Ј-UTRs that might have a role in the control of mRNA stability or translation efficiency (18,19).…”

Cross-talk between 4-1BB and TLR1–TLR2 Signaling in CD8+ T Cells Regulates TLR2′s Costimulatory Effects

“…The 4-1BB gene has three distinct promoter regions (PI, PII, and PIII), of which PI and PII each have an AP-1 and NF-κB binding site (21). We used a chromatin immunoprecipitation assay to assess NF-κB (p65) and AP-1(cJun) binding to each the PI and PII promoter regions at different time points after T-cell activation.…”