Identification of a Silencer, Enhancer, and Basal Promoter Region in the Human CD95 (Fas/APO-1) Gene

Abstract

Genomic clones for the human CD95 (Fas/APO-1) and CD40 genes have been isolated and 2.3 kb of the CD95 and 0.8 kb of the CD40 gene 5'-flanking regions sequenced. Comparisons of the human CD95 gene with the human CD40 and the murine CD40 and TNFR-II genes showed a low degree of sequence similarity. However, dot matrix analyses revealed conservation of two stretches between human CD95 (-387 to -362 and -288 to 261 in CD95) and murine TNFR-II genes. Additionally, TCCTCC motifs are present within 400 bp up-stream of the ATG of all genes examined. Repeated interferon-beta (IFN-beta) silencer B motifs and a lysozyme silencer 1 motif have been found in the CD95 gene at approximately -1,600 and -1,100, respectively. Sequence comparison of the 5'-flanking regions of the murine and human CD40 genes revealed the presence of a conserved AP-4 site and two SP-1 sites. CD95, CD40, and TNFR-II genes all lack classical TATA and CAAT boxes. However, a strongly increased frequency of CpG dinucleotides was found. Primer extension analysis revealed multiple transcriptional start sites in the CD95 gene, where the usage of individual start sites appeared to be cell type-specific. Functional analysis, using reporter constructs and transient transfections, identified a silencer activity residing between nucleotide positions -1,781 and -1007 and a strong enhancer region between -1,007 and -425 in the human CD95 gene. The region between -425 and -1 retained a basal promoter activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Increased spontaneous in vitro apoptosis in double negative T cells of humans with a fas/apo-1 mutation

“…The increased expression of Fas/Apo-1 as the only peculiar finding shared by mother and son might be a candidate. Alternatively, as multiple transcriptional start sites have been found in the fas/apo-1 promoter region, gene regulation may account to the pathogenesis of ALPS/ CSS (Rudert et al, 1995). It seems reasonable that episodes of pancytopenia during infection as observed in our patient result from stimulation of fas/apo-1 transcription as demonstrated for influenza infection by Wada and coworkers (Wada et al, 1995).…”

“…Patient RT and his father were shown to carry a point mutation at position 804 resulting in an A 804 C exchange when compared with the published sequences (Behrmann et al, 1994;Rudert et al, 1995). This mutation causes a single amino acid exchange at position 268 of the Fas/Apo-1 molecule (Q 268 P).…”

“…PCR was performed in a final volume of 10 ml with 120 mM dNTPs each, 3 mM MgCl 2 , 0.5 mM each primer and 0.8 U Taq using a hot air rapid cycler (Idaho Technologies, Birfeld, Switzerland). Primers were designed according to published sequences (Behrmann et al, 1994;Rudert et al, 1995). Primers used for analysis of transcription quantities of fas/apo-1 and fasL and for sequencing purposes are shown in Table 3.…”

Hypermethylated promoter region of DR3, the death receptor 3 gene, in rheumatoid arthritis synovial cells

“…Previous studies have shown that plenty of CpG motifs exist in the promoter region of apoptosis-inducing TNF receptor superfamily genes (29) and that apoptotic signaling pathways are often subjected to epigenetic gene silencing (19,30). However, with the exception of the study by Petak et al (31), who showed an inverse correlation between the methylation status of the Fas gene promoter and Fas protein expression by comparing different tumor cell lines, the promoter activity of apoptosis-inducing genes was not directly studied in the same cell.…”

TNF combined with IFN-α accelerates NF-κB-mediated apoptosis through enhancement of Fas expression in colon cancer cells

“…Functional analysis using reporter constructs and transient transfections identified a silencer activity residing in the promoter of the Fas gene. 38 Yin Yang-1 (YY1) is a DNAbinding zinc-finger transcription factor functioning as an activator, a repressor, and an initiator of transcription. 39 Nitric oxide (NO) has been implicated in transcriptional control, and serves as an intracellular second messenger to modify gene expression.…”