title: Relationship between differentially expressed mRNA and mRNA-protein correlations in a xenograft model system.
abstract: Differential mRNA expression studies implicitly assume that changes in mRNA expression have biological meaning, most likely mediated by corresponding changes in protein levels. Yet studies into mRNA-protein correspondence have shown notoriously poor correlation between mRNA and protein expression levels, creating concern for inferences from only mRNA expression data. However, none of these studies have examined in particular differentially expressed mRNA. Here, we examined this question in an ovarian cancer xenograft model. We measured protein and mRNA expression for twenty-nine genes in four drug-treatment conditions and in untreated controls. We identified mRNAs differentially expressed between drug-treated xenografts and controls, then analysed mRNA-protein expression correlation across a five-point time-course within each of the four experimental conditions. We evaluated correlations between mRNAs and their protein products for mRNAs differentially expressed within an experimental condition compared to those that are not. We found that differentially expressed mRNAs correlate significantly better with their protein product than non-differentially expressed mRNAs. This result increases confidence for the use of differential mRNA expression for biological discovery in this system, as well as providing optimism for the usefulness of inferences from mRNA expression in general.
authors.affiliation: School of Biology, University of St Andrews, St Andrews, Fife, KY16 9TH, UK.
authors.forename: Antonis
authors.initials: A
authors.lastname: Koussounadis
authors.affiliation: Division of Pathology, University of Edinburgh, Edinburgh, EH4 2XU, UK.
authors.forename: Simon P
authors.initials: SP
authors.lastname: Langdon
authors.affiliation: School of Medicine, University of St Andrews, St Andrews, Fife, KY16 9TF, UK.
authors.forename: In Hwa
authors.initials: IH
authors.lastname: Um
authors.affiliation: School of Medicine, University of St Andrews, St Andrews, Fife, KY16 9TF, UK.
authors.forename: David J
authors.initials: DJ
authors.lastname: Harrison
authors.affiliation: School of Biology, University of St Andrews, St Andrews, Fife, KY16 9TH, UK.
authors.forename: V Anne
authors.initials: VA
authors.lastname: Smith
mesh_terms: D000818:Animals; D005260:Female; D015870:Gene Expression / Q000235:genetics*; D020869:Gene Expression Profiling / Q000379:methods; D015972:Gene Expression Regulation, Neoplastic / Q000235:genetics*; D064593:Heterografts / Q000378:metabolism*; D051379:Mice; D008819:Mice, Nude; D010051:Ovarian Neoplasms / Q000235:genetics; D011506:Proteins / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics
chemical_list: D011506:Proteins; D012333:RNA, Messenger