title: Werner's syndrome helicase participates in transcription of phenobarbital-inducible CYP2B genes in rat and mouse liver.
abstract: Werner's syndrome (WS) is a rare human autosomal recessive segmental progeroid syndrome clinically characterized by atherosclerosis, cancer, osteoporosis, type 2 diabetes mellitus and ocular cataracts. The WRN gene codes for a RecQ helicase which is present in many tissues. Although the exact functions of the WRN protein remain unclear, accumulating evidence suggests that it participates in DNA repair, replication, recombination and telomere maintenance. It has also been proposed that WRN participates in RNA polymerase II-dependent transcription. However no promoter directly targeted by WRN has yet been identified. In this work, we report mammalian genes that are WRN targets. The rat CYP2B2 gene and its closely related mouse homolog, Cyp2b10, are both strongly induced in liver by phenobarbital. We found that there is phenobarbital-dependent recruitment of WRN to the promoter of the CYP2B2 gene as demonstrated by chromatin immunoprecipitation analysis. Mice homozygous for a Wrn mutation deleting part of the helicase domain showed a decrease in basal and phenobarbital-induced CYP2B10 mRNA levels compared to wild type animals. The phenobarbital-induced level of CYP2B10 protein was also reduced in the mutant mice. Electrophoretic mobility shift assays showed that WRN can participate in the formation of a complex with a specific sequence within the CYP2B2 basal promoter. Hence, there is a WRN binding site in a region of DNA sequence to which WRN is recruited in vivo. Taken together, these results suggest that WRN participates in transcription of CYP2B genes in liver and identifies the first physical interaction between a specific promoter sequence and WRN.
authors.affiliation: Centre de recherche en cancérologie de l'Université Laval, L'Hôtel-Dieu de Québec, CHUQ, Québec, Canada.
authors.forename: Antoine Amaury
authors.initials: AA
authors.lastname: Lachaud
authors.forename: Sacha
authors.initials: S
authors.lastname: Auclair-Vincent
authors.forename: Laurent
authors.initials: L
authors.lastname: Massip
authors.forename: Etienne
authors.initials: E
authors.lastname: Audet-Walsh
authors.forename: Michel
authors.initials: M
authors.lastname: Lebel
authors.forename: Alan
authors.initials: A
authors.lastname: Anderson
mesh_terms: D000818:Animals; D001189:Aryl Hydrocarbon Hydroxylases / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D002843:Chromatin / Q000235:genetics / Q000378:metabolism; D051544:Cytochrome P-450 CYP3A / Q000096:biosynthesis / Q000235:genetics; D000072467:Cytochrome P450 Family 2; D016503:Drug Delivery Systems; D004790:Enzyme Induction / Q000187:drug effects / Q000235:genetics; D017353:Gene Deletion; D008099:Liver / Q000187:drug effects / Q000201:enzymology* / Q000473:pathology; D008297:Male; D008565:Membrane Proteins / Q000096:biosynthesis / Q000235:genetics; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D010634:Phenobarbital / Q000494:pharmacology*; D021381:Protein Transport / Q000187:drug effects / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D053484:RecQ Helicases / Q000096:biosynthesis / Q000172:deficiency / Q000235:genetics*; D013250:Steroid Hydroxylases / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D015533:Transcriptional Activation / Q000187:drug effects / Q000235:genetics*; D014898:Werner Syndrome / Q000201:enzymology / Q000235:genetics
chemical_list: D002843:Chromatin; D008565:Membrane Proteins; D013250:Steroid Hydroxylases; D001189:Aryl Hydrocarbon Hydroxylases; C101679:Cyp2b10 protein, mouse; C496508:Cyp3a11 protein, mouse; D051544:Cytochrome P-450 CYP3A; D000072467:Cytochrome P450 Family 2; C025619:steroid 16-beta-hydroxylase; D053484:RecQ Helicases; D010634:Phenobarbital