ABSTRACT
A large-scale search for the genetic variants with a bias in the representation of alleles in transcriptome data (AE SNPs) and the binding sites in microRNA 3'-UTRs was performed and their functional significance was assessed using massively parallel reporter assay (MPRA). Of the 629,559 associated "SNP-gene" pairs (eQTLs) discovered in the human liver tissue according to the GTEx Analysis V8 data, 4394 polymorphic positions in the 3'-UTRs of the genes, which represent the eQTLs for these genes were selected. The TargetScanHuman 7.0 algorithm and PolymiRTS database were searched for the potential microRNA-binding sites. Of the predicted microRNA sites affected by eQTL-SNPs, we selected 51 sites with the best evidence of functionality according to Ago2-CLIP-seq, CLEAR-CLIP, and eCLIP-seq for RNA-binding proteins. For MPRA, a library of the plasmids carrying the main and alternative alleles for each AE SNP (in total, 102 constructs) was created. Allele-specific expression for 6 SNPs was detected by transfection of the HepG2 cell line with the constructed plasmid library and sequencing of target DNA and RNA sequences using the Illumina (MiSeq) platform.
Subject(s)
3' Untranslated Regions , Alleles , MicroRNAs , Polymorphism, Single Nucleotide , Humans , Polymorphism, Single Nucleotide/genetics , MicroRNAs/genetics , MicroRNAs/metabolism , Hep G2 Cells , Binding Sites/genetics , 3' Untranslated Regions/genetics , High-Throughput Nucleotide Sequencing/methods , Genes, Reporter/genetics , Liver/metabolism , Argonaute Proteins/genetics , Argonaute Proteins/metabolism , Transcriptome/geneticsABSTRACT
Cardiovascular diseases (CVDs), the leading cause of death worldwide, generally refer to a range of pathological conditions with the involvement of the heart and the blood vessels. A sizable fraction of the susceptibility loci is known, but the underlying mechanisms have been established only for a small proportion. Therefore, there is an increasing need to explore the functional relevance of trait-associated variants and, moreover, to search for novel risk genetic variation. We have reported the bioinformatic approach allowing effective identif ication of functional non-coding variants by integrated analysis of genome-wide data. Here, the analysis of 1361 previously identif ied regulatory SNPs (rSNPs) was performed to provide new insights into cardiovascular risk. We found 773,471 coding co-segregating markers for input rSNPs using the 1000 Genomes Project. The intersection of GWAS-derived SNPs with a relevance to cardiovascular traits with these markers was analyzed within a window of 10 Kbp. The effects on the transcription factor (TF) binding sites were explored by DeFine models. Functional pathway enrichment and protein-protein interaction (PPI) network analyses were performed on the targets and the extended genes by STRING and DAVID. Eighteen rSNPs were functionally linked to cardiovascular risk. A signif icant impact on binding sites of thirteen TFs including those involved in blood cells formation, hematopoiesis, macrophage function, inf lammation, and vasoconstriction was found in K562 cells. 21 rSNP gene targets and 5 partners predicted by PPI were enriched for spliceosome and endocytosis KEGG pathways, endosome sorting complex and mRNA splicing REACTOME pathways. Related Gene Ontology terms included mRNA splicing and processing, endosome transport and protein catabolic processes. Together, the f indings provide further insight into the biological basis of CVDs and highlight the importance of the precise regulation of splicing and alternative splicing.
Subject(s)
Bacterial Outer Membrane Proteins/genetics , Oligonucleotide Array Sequence Analysis/methods , Receptors, Cell Surface/genetics , Bacterial Outer Membrane Proteins/chemistry , Base Sequence/genetics , Binding Sites/genetics , Protein Binding/genetics , Receptors, Cell Surface/chemistry , Transcription Factors/chemistry , Transcription Factors/geneticsABSTRACT
To reveal the mechanism of tumor-suppressing activity of FOXA proteins in liver, a search for potential target genes of these transcription factors involved in proliferation control was carried out. In the first step, we have used data from the literature concerning gene expression in mouse liver (high content of FOXA proteins) and kidney (FOXA expression is absent) obtained by hybridization on microchips. A search for FOXA binding sites in regulatory regions of forty differentially expressing genes involved in proliferation control was carried out using the computer method SITECON. Eleven genes containing clusters of potential FOXA sites incorporating 3-6-fold repeats of TTTG were revealed. The FOXA-specific interaction with such microsatellite sites was confirmed by gel-retardation technique using the GST-fused protein containing the DNA-binding domain of FOXA2. Six genes containing clusters of confirmed binding sites--Cul2, Cdc73, Ptk, Pdcd, Creb, and Ppp2r5d--were selected. The effect of hepatocarcinogen orthoaminoazotoluene (OAT), which lowers the FOXA activity, on expression of these genes was studied by the real-time PCR. OAT was shown to increase sharply the level of mRNA of the Cul2 and Cdc73 genes.
Subject(s)
Gene Expression , Hepatocyte Nuclear Factors/metabolism , Liver/metabolism , Animals , Binding Sites , Carcinogens/pharmacology , Cell Proliferation , Gene Expression/drug effects , Liver/drug effects , Male , Mice , RNA, Messenger/biosynthesis , Regulatory Elements, Transcriptional , o-Aminoazotoluene/pharmacologyABSTRACT
o-Aminoazotoluene was more potent than 3'-methyl-4-dimethylaminoazobenzene in modulating glucocorticoid induction of tyrosine aminotransferase and DNA-binding activity of FOXA (HNF3) in 12-day-old ICR mice. In adult animals, induction of tyrosine aminotransferase and FOXA activity were modulated by o-aminoazotoluene, while 3'-methyl-4-dimethylaminoazobenzene was ineffective. Our results suggest that FOXA proteins determine glucocorticoid induction of tyrosine aminotransferase in mice (similarly to rats).
