Project description:RNA was labeled in BL41 cells by culturing cells for 60 min in media containing 100µM 4sU. Tc-RNA was separated into nt- and p-RNA. All three RNA subsets were subjected to microarray analysis. Only probe sets providing present calls in all RNA samples/subsets were included into the analysis We used microarrays to determine half-lives of mRNAs expressed in BL41 cells Keywords: Determination of mRNA half-life in human B-cells
Project description:This SuperSeries is composed of the following subset Series:; GSE9973: Half-life determination for human B-cells (BL41); GSE9975: newly transcribed RNA (nt-RNA) for IFN alpha and gamma time course; GSE9977: Expression data from NIH-3T3 cells treated with mock, 100 U/ml IFN alpha or 100 U/ml gamma for 1or 3h; GSE10011: Expression data from NIH-3T3 cells used for half-life determination Experiment Overall Design: Refer to individual Series
Project description:Transcript abundance results from the balance between transcription and mRNA decay, and varies pervasively in humans. We have examined the effect of DNA variation on mRNA half-life differences by conducting a genome-wide survey of mRNA stability in seven human HapMap lymphoblastoid cell lines (LCLs). We determined the mRNA half-life for each gene from the ratio of 4-thio-uridine (4sU)-labeled nascent RNAs to total RNAs. 5,145 (46%) of 11,132 analyzed genes showed inter-individual mRNA half-life differences at a false discovery rate, FDR<0.05. As previously reported, we found transcription to be the main factor influencing transcript abundance. Although mRNA half-life explained only ~6% of transcript abundance on average, it explained ~16% for the subset of genes (~10%) showing inter-individual mRNA half-life differences (P<0.001). We confirmed previously reported correlations of mRNA half-life with transcript length, 3’-UTR length, and number of exon-junctions per kb of transcript. The number of miRNA targets in 3’-UTRs was negatively correlated with half-life (P=2.2×10-16), a new observation that is consistent with the role of miRNA in inducing mRNA degradation. Notably, coding GC and GC3 content showed positive correlations with mRNA half-life in genes with inter-individual mRNA half-life differences, implying a role of mRNA stability in shaping synonymous codon usage bias. Consistently, G or C alleles of coding SNPs were found associated with longer mRNA half-life (P=0.021). As expected, we also found that nonsense SNPs were associated with shorter mRNA half-life (P=0.009). Our results strongly suggest that inter-individual mRNA stability differences are widespread and affected by DNA sequence and composition variation.
Project description:Transcript abundance results from the balance between transcription and mRNA decay, and varies pervasively in humans. We have examined the effect of DNA variation on mRNA half-life differences by conducting a genome-wide survey of mRNA stability in seven human HapMap lymphoblastoid cell lines (LCLs). We determined the mRNA half-life for each gene from the ratio of 4-thio-uridine (4sU)-labeled nascent RNAs to total RNAs. 5,145 (46%) of 11,132 analyzed genes showed inter-individual mRNA half-life differences at a false discovery rate, FDR<0.05. As previously reported, we found transcription to be the main factor influencing transcript abundance. Although mRNA half-life explained only ~6% of transcript abundance on average, it explained ~16% for the subset of genes (~10%) showing inter-individual mRNA half-life differences (P<0.001). We confirmed previously reported correlations of mRNA half-life with transcript length, 3M-bM-^@M-^Y-UTR length, and number of exon-junctions per kb of transcript. The number of miRNA targets in 3M-bM-^@M-^Y-UTRs was negatively correlated with half-life (P=2.2M-CM-^W10-16), a new observation that is consistent with the role of miRNA in inducing mRNA degradation. Notably, coding GC and GC3 content showed positive correlations with mRNA half-life in genes with inter-individual mRNA half-life differences, implying a role of mRNA stability in shaping synonymous codon usage bias. Consistently, G or C alleles of coding SNPs were found associated with longer mRNA half-life (P=0.021). As expected, we also found that nonsense SNPs were associated with shorter mRNA half-life (P=0.009). Our results strongly suggest that inter-individual mRNA stability differences are widespread and affected by DNA sequence and composition variation. A total of 7 HapMap LCLs were used to measure mRNA half-life. Total RNAs and the 4sU-labeled-newly synthesized RNAs (nascent RNAs) were isolated from the same cell culture and were assayed simultaneously with human Exon array. For 3 LCLs, we included 3 biological replicates (i.e., independent cell cultures) and for 1 LCL we also included technical duplicates. mRNA half-life was calculated from the ratio of nascent RNAs/total RNAs. We used ANOVA to test inter-individual difference of mRNA half-life between 3 subjects who have biological replicates and technical duplicates. We examined the Spearman rank correlation of mRNA half-life with a number of gene features, including transcript length, intron length, 5'-UTR length and folding energy, 3'-UTR length and folding energy, microRNA target sites, GC and GC3 contents, etc. We also performed linear regression to test the effects of specific type of sequence variants (nonsense SNPs, SNPs within miRNA target sites, and coding synonymous and nonsynonymous SNPs) on mRNA half-life across 3 subjects that have whole genome sequencing data available (1000 genome project June 2011 release).
Project description:The change in abundance of individual mRNAs as cells differentiate through neurodevelopmental stages is generally attributed to transcription level alterations while the potential contribution of mRNA half-life is commonly overlooked. While some genes are regulated solely by transcription, others may be regulated by mRNA half-life only, or genes with changed transcription rates could be buffered by compensating half-life decreases or even boosted by amplifying half-life increases. In addition, during neurodevelopment there is widespread 3ʹUTR lengthening that could be shaped by differential shifts in the stability of transcript isoforms. Here we measure transcription rate and mRNA half-life changes during induced Pluripotent Stem Cell-derived neuronal development using RATE-seq at the resolution of gene isoforms. We found that during transitions to progenitor and neuron stages, transcript buffering occurs in up to half of all genes. Half-life only changes are observed in as many genes as transcription rate only changes, and almost 10% of genes exhibit transcript boosting. Global mRNA half-life decreases two-fold in neurons relative to iPSCs. The observed mRNA destabilization differentially affects gene isoforms and contributes to 3ʹUTR lengthening. Small RNA sequencing further captured an increase in microRNA copy number per cell. We propose that mRNA destabilization and 3ʹUTR lengthening are driven in part by an increase in microRNA load. Our findings identify mRNA stability mechanisms in human neurodevelopment that regulate gene and isoform level abundance and provide a precedent for similar post-transcriptional regulatory events as other tissues develop.