title: Distinct proteins encoded by alternative transcripts of the PURG gene, located contrapodal to WRN on chromosome 8, determined by differential termination/polyadenylation.
abstract: A gene encoding a new member of the Pur protein family, Purgamma, has been detected upstream of, and contrapodal to, the gene encoding the Werner syndrome helicase, Wrn, at human chromosome band 8p11-12. Both the PURG and WRN genes initiate transcription at multiple sites, the major clusters of which are approximately 90 bp apart. A segment containing this region strongly promotes transcription of a reporter gene in both directions. Both promoters are TATA-less and CAAT-less and both are positively regulated by Sp1 elements. While promoter elements for the two genes are interleaved, in the contrapodal direction, certain elements critical for each gene are distinct. Sequencing of cDNAs for Purgamma mRNA reveals that two alternative coding sequences are generated from a single gene, resulting in different Purgamma C-termini. PURG-A mRNA consists of a single intronless transcript of approximately 3 kb. PURG-B mRNA results from transcription through the PURG-A polyadenylation site and splicing out of an intron of >30 kb. In this unique example of a switch, splicing of a single intron either occurs or does not occur depending upon differential termination/polyadenylation. PURG-B is the primary PURG transcript detected in testis, but it is undetectable in all members of a normal adult tissue cDNA panel. PURG-A levels are low or undetectable in the normal tissue panel, but they are greatly elevated in all members of a tumor tissue panel. PURG-B is detected in several tumor panel members.
authors.affiliation: Department of Pathology and the D. H. Ruttenberg Cancer Center, Box 1194, Mount Sinai School of Medicine, New York, NY 10029, USA.
authors.forename: Hong
authors.initials: H
authors.lastname: Liu
authors.forename: Edward M
authors.initials: EM
authors.lastname: Johnson
mesh_terms: D020121:5' Untranslated Regions / Q000032:analysis / Q000235:genetics; D017398:Alternative Splicing / Q000235:genetics*; D002898:Chromosomes, Human, Pair 8 / Q000235:genetics*; D004265:DNA Helicases / Q000737:chemistry / Q000235:genetics*; D004268:DNA-Binding Proteins; D005090:Exodeoxyribonucleases; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D023061:Gene Order / Q000235:genetics; D006367:HeLa Cells; D006801:Humans; D007438:Introns / Q000235:genetics; D008297:Male; D008969:Molecular Sequence Data; D009928:Organ Specificity; D020161:Physical Chromosome Mapping; D026723:Polyadenylation; D011401:Promoter Regions, Genetic / Q000235:genetics*; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D053484:RecQ Helicases; D013737:Testis / Q000378:metabolism; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics*; D024363:Transcription Initiation Site; D014158:Transcription, Genetic / Q000235:genetics*; D014407:Tumor Cells, Cultured; D000071657:Werner Syndrome Helicase
chemical_list: D020121:5' Untranslated Regions; D004268:DNA-Binding Proteins; C456379:PURG protein, human; D012333:RNA, Messenger; D014157:Transcription Factors; D005090:Exodeoxyribonucleases; D004265:DNA Helicases; D053484:RecQ Helicases; C098785:WRN protein, human; D000071657:Werner Syndrome Helicase