THE MOUSE-TUMOR NECROSIS FACTOR-RECEPTOR 2 GENE - GENOMIC STRUCTURE AND CHARACTERIZATION OF THE 2 TRANSCRIPTS

The mouse TNFR2 gene has been cloned, sequenced, and characterized as a gene spanning >44 kb of the genome. By alignment of five genomic clo nes we have established that TNFR2 consists of 10 exons and 9 introns with exons ranging in sine from 35 bp to 2.6 kb and introns ranging fr om 322 bp to >16 kb, All splice acceptor and donor sites conform to th e canonical AG/GT rule. The translation initiation and termination sit es are located in exon 1 and 10, respectively. Although TNFR2 lacks a canonical TATA box, the gene is transcribed from a unique start site l ocated 70 bp upstream of the ATG initiation codon that conforms to the consensus Inr motif, Several cis-elements for transcription factors w ere identified in the 5' flanking region, including NF-1, Sp-1, AP2, g amma-IREI and NF-kappa B motifs, Functional analysis indicates that th e region -705/-412 contains a negative cis-acting element and that the minimal promoter contains motifs that confer LPS inducibility, Two mo use TNFR2 mRNAs of 3.2 and 4.1 kb are detected by Northern blot analys is, but until now their origin has not been explained. No evidence of alternative splicing of the coding exons was found. However, hybridiza tion studies and amplification of cDNA ends suggest the use of a nonca nonical polyadenylation signal in the untranslated region of exon 10, A comparative analysis of the 3' untranslated regions of the human and mouse TNFR2 genes shows highly divergent 3' ends. The possibility of an ancestral mouse TNFR2 mRNA similar to the short transcript is discu ssed. (C) 1998 Academic Press.