title: Detection, validation, and downstream analysis of allelic variation in gene expression.
abstract: Common sequence variants within a gene often generate important differences in expression of corresponding mRNAs. This high level of local (allelic) control-or cis modulation-rivals that produced by gene targeting, but expression is titrated finely over a range of levels. We are interested in exploiting this allelic variation to study gene function and downstream consequences of differences in expression dosage. We have used several bioinformatics and molecular approaches to estimate error rates in the discovery of cis modulation and to analyze some of the biological and technical confounds that contribute to the variation in gene expression profiling. Our analysis of SNPs and alternative transcripts, combined with eQTL maps and selective gene resequencing, revealed that between 17 and 25% of apparent cis modulation is caused by SNPs that overlap probes rather than by genuine quantitative differences in mRNA levels. This estimate climbs to 40-50% when qualitative differences between isoform variants are included. We have developed an analytical approach to filter differences in expression and improve the yield of genuine cis-modulated transcripts to approximately 80%. This improvement is important because the resulting variation can be successfully used to study downstream consequences of altered expression on higher-order phenotypes. Using a systems genetics approach we show that two validated cis-modulated genes, Stk25 and Rasd2, are likely to control expression of downstream targets and affect disease susceptibility.
authors.affiliation: Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, Tennessee 38163, USA. dciobanu2@unl.edu
authors.forename: Daniel C
authors.initials: DC
authors.lastname: Ciobanu
authors.forename: Lu
authors.initials: L
authors.lastname: Lu
authors.forename: Khyobeni
authors.initials: K
authors.lastname: Mozhui
authors.forename: Xusheng
authors.initials: X
authors.lastname: Wang
authors.forename: Manjunatha
authors.initials: M
authors.lastname: Jagalur
authors.forename: John A
authors.initials: JA
authors.lastname: Morris
authors.forename: William L
authors.initials: WL
authors.lastname: Taylor
authors.forename: Klaus
authors.initials: K
authors.lastname: Dietz
authors.forename: Perikles
authors.initials: P
authors.lastname: Simon
authors.forename: Robert W
authors.initials: RW
authors.lastname: Williams
mesh_terms: D020413:3' Untranslated Regions / Q000235:genetics; D000483:Alleles; D017398:Alternative Splicing; D000818:Animals; D019295:Computational Biology; D030541:Databases, Genetic; D015870:Gene Expression / Q000235:genetics*; D020869:Gene Expression Profiling; D006801:Humans; D051379:Mice; D020411:Oligonucleotide Array Sequence Analysis; D016133:Polymerase Chain Reaction; D020641:Polymorphism, Single Nucleotide; D040641:Quantitative Trait Loci / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D015203:Reproducibility of Results; D017422:Sequence Analysis, DNA; D014158:Transcription, Genetic
chemical_list: D020413:3' Untranslated Regions; D012333:RNA, Messenger