A spatiotemporal dynamic atlas of circular RNAs unraveled extensive intraspecific and developmental variation in maize
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ABSTRACT:
ORGANISM(S): Zea mays
PROVIDER: GSE199881 | GEO | 2024/03/30
REPOSITORIES: GEO
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Project description:Purpose: The goals of this study are to identify Mutator insertion sites and determine the affect of these insertions on nearby genes Methods: Wiseq-based Mu element profiling was performed as described previously using B73/Mo17 F1 hybrid progeny seedlings. The B73 parent was carried Mutator activity that had been introgressed into the B73 genetic background. The Mo17 parent lacked active Mu elements. Thus, all new insertions were into the B73 genome. Genomic DNA was extracted from 6-day-old seedlings of B73/Mo17 hybrid plants. Amplicon-based enrichment of Mu flanking DNA was then performed. The purified PCR products were subject to Miseq-based Wideseq pipeline at Purdue Genomics Core Facility (https://www.purdue.edu/hla/sites/genomics/wideseq-2/). Wideseq reads were mapped to the B73 reference genome as described previously. By identifying the Mu target site duplications (TSDs), a set of genes targeted by Mu insertions that segregated in hybrid progeny was obtained and those containing B73/Mo17 SNPs in their mRNA sequences were used for allele-specific expression analysis. Because new insertions were into the B73 genome, the effect of these insertions would be expected to be specific in all cases to the B73 allele. To quantify the allele frequency, we performed RT-PCR followed by Wideseq from the identical shoot tissues of the hybrid seedlings mentioned above. Total RNA was extracted using the RNA Extraction Kit (Zymo) and cDNAs were synthesized using Promega M-MLV Reverse Transcriptase. For for a subset of 16 genes that carried SNPs, RNA fragments containing B73/Mo17 SNPs were amplified by RT-PCR. Libraries were prepared using an mRNA preparation kit (Illumina) following a standard protocol (https://www.purdue.edu/hla/sites/genomics/wi-deseq-2/). The RT-PCR products were then sequenced by the “WideSeq” pipeline. Results: A knockdown index was deduced by normalizing the observed ratio to that observed in genes that lacked Mu insertions in both genetic backgrounds for each insertion. We found that none of the four promoter insertions changed the expression of nearby genes. A quarter of 5’ UTR insertions (5 out of 20) caused knockout or strong knockdown effects and one of seven intronic insertions resulted in a knockout effect. Collectively, of a total of 33 Mu insertions, all of which were within 200 bp of genes, only 11 significantly reduced gene expression, and only two knocked it out completely. Conclusions: These results indicate that that Mu element insertions near TSSs of host genes are often associated with quantitative and in many cases neglectable functional consequences on nearby gene expression.
2020-05-09 | GSE146647 | GEO
Project description:Maize earshoot is a metabolic sink espcially related to nitrogen metabolism. Studies on the transcriptomic and metabolic changes occuring in earshoot can provide interesting answers about the nitrogen metabolic potential of the maize variety under study. B73 X Mo17 is a model maize hybrid. Developing earshoots from this genotype grown at nitrogen-deficient and nitrogen-sufficient conditions were sampled, processed and analyzed through microarray technology. B73 X Mo17 hybrid_developing earshoot microarray data: Technical replicates, no biological replicates
2010-01-13 | E-GEOD-17932 | biostudies-arrayexpress
Project description:The contribution of epigenetic alterations to natural variation for gene transcription levels remains unclear. In this study, we investigated the functional targets of the maize chromomethylase ZMET2 in multiple inbred lines to determine whether epigenetic changes conditioned by this chromomethylase are conserved or variable within the species. Gene expression microarrays were hybridized with RNA samples from the inbred lines B73 and Mo17, and from near-isogenic derivatives containing the loss-of-function allele zmet2-m1. A set of 126 genes that displayed statistically significant differential expression in zmet2 mutants relative to wild-type plants in at least one of the two genetic backgrounds were identified. Analysis of the transcript levels in both wild-type and mutant individuals revealed that only 10% of these genes were affected in zmet2 mutants in both B73 and Mo17 genetic backgrounds. Over 80% of the genes with expression patterns affected by zmet2 mutations display variation for gene expression between wild-type B73 and Mo17 plants. Further analysis was performed for seven genes that were transcriptionally silent in wild-type B73, but expressed in B73 zmet2-m1, wild-type Mo17 and Mo17 zmet2-m1 lines. Mapping experiments confirmed that the expression differences in wild-type B73 relative to Mo17 inbreds for these genes were caused by cis-acting regulatory variation. Methylation-sensitive PCR and bisulphite sequencing demonstrated that for five of these genes the CpNpG methylation in the wild-type B73 genetic background was substantially decreased in the B73 zmet2-m1 mutant and in wild-type Mo17. A survey of eight maize inbreds reveals that each of these five genes exhibit transcriptionally silent and methylated states in some inbred lines and unmethylated, expressed states in other inbreds, providing evidence for natural variation in epigenetic states for some maize genes. Keywords: mutant versus wild-type comparison in two inbred genotypes
2007-12-01 | GSE8188 | GEO
Project description:Microarray analysis of gene expression patterns in immature ear, seedling, and embryo tissues from the maize inbred lines B73 and Mo17 identified numerous genes with variable expression. Some genes had detectable expression in only one of the two inbreds; most of these genes were detected in the genomic DNA of both inbreds, indicating that the expression differences are likely caused by differential regulation rather than by differences in gene content. Gene expression was also monitored in the reciprocal F1 hybrids B73xMo17 and Mo17xB73. The reciprocal F1 hybrid lines did not display parental effects on gene expression levels. Approximately 80% of the differentially expressed genes displayed additive expression patterns in the hybrids relative to the inbred parents. The approximately 20% of genes that display nonadditive expression patterns tend to be expressed at levels within the parental range, with minimal evidence for novel expression levels greater than the high parent or less than the low parent. Analysis of allele-specific expression patterns in the hybrid suggested that intraspecific variation in gene expression levels is largely attributable to cis-regulatory variation in maize. Collectively, our data suggest that allelic cis-regulatory variation between B73 and Mo17 dictates maintenance of inbred allelic expression levels in the F1 hybrid, resulting in additive expression patterns. Experiment Overall Design: Affymetrix expression profiling was used to study gene expression in 19 day after pollination embryo tissue of maize. Three biological replicates were performed for four different genotypes; B73, Mo17, B73xMo17 and Mo17xB73.
2008-06-16 | E-GEOD-8179 | biostudies-arrayexpress
Project description:Microarray analysis of gene expression patterns in immature ear, seedling, and embryo tissues from the maize inbred lines B73 and Mo17 identified numerous genes with variable expression. Some genes had detectable expression in only one of the two inbreds; most of these genes were detected in the genomic DNA of both inbreds, indicating that the expression differences are likely caused by differential regulation rather than by differences in gene content. Gene expression was also monitored in the reciprocal F1 hybrids B73xMo17 and Mo17xB73. The reciprocal F1 hybrid lines did not display parental effects on gene expression levels. Approximately 80% of the differentially expressed genes displayed additive expression patterns in the hybrids relative to the inbred parents. The approximately 20% of genes that display nonadditive expression patterns tend to be expressed at levels within the parental range, with minimal evidence for novel expression levels greater than the high parent or less than the low parent. Analysis of allele-specific expression patterns in the hybrid suggested that intraspecific variation in gene expression levels is largely attributable to cis-regulatory variation in maize. Collectively, our data suggest that allelic cis-regulatory variation between B73 and Mo17 dictates maintenance of inbred allelic expression levels in the F1 hybrid, resulting in additive expression patterns. Experiment Overall Design: Affymetrix expression profiling was used to study gene expression in aerial tissue from 11-day seedlings of maize. Three biological replicates were performed for four different genotypes; B73, Mo17, B73xMo17 and Mo17xB73.
2008-06-17 | E-GEOD-8174 | biostudies-arrayexpress
Project description:Microarray analysis of gene expression patterns in immature ear, seedling, and embryo tissues from the maize inbred lines B73 and Mo17 identified numerous genes with variable expression. Some genes had detectable expression in only one of the two inbreds; most of these genes were detected in the genomic DNA of both inbreds, indicating that the expression differences are likely caused by differential regulation rather than by differences in gene content. Gene expression was also monitored in the reciprocal F1 hybrids B73xMo17 and Mo17xB73. The reciprocal F1 hybrid lines did not display parental effects on gene expression levels. Approximately 80% of the differentially expressed genes displayed additive expression patterns in the hybrids relative to the inbred parents. The approximately 20% of genes that display nonadditive expression patterns tend to be expressed at levels within the parental range, with minimal evidence for novel expression levels greater than the high parent or less than the low parent. Analysis of allele-specific expression patterns in the hybrid suggested that intraspecific variation in gene expression levels is largely attributable to cis-regulatory variation in maize. Collectively, our data suggest that allelic cis-regulatory variation between B73 and Mo17 dictates maintenance of inbred allelic expression levels in the F1 hybrid, resulting in additive expression patterns. Experiment Overall Design: Affymetrix expression profiling was used to study gene expression in immature ear tissue from maize. Three biological replicates were performed for four different genotypes; B73, Mo17, B73xMo17 and Mo17xB73.
2008-06-16 | E-GEOD-8176 | biostudies-arrayexpress
Project description:Small RNAs (sRNAs) are hypothesized to contribute to hybrid vigor because they maintain genome integrity, contribute to genetic diversity, and control gene expression. We used Illumina sequencing to assess how sRNA populations vary between two maize inbred lines (B73, Mo17) and their hybrid. We sampled sRNAs from the seedling shoot apex and the developing ear, two rapidly growing tissues that program the greater growth of maize hybrids. We found that parental differences in siRNAs primarily originate from repeat regions. Although the maize genome contains greater number and complexity of repeats compared to Arabidopsis or rice, we confirmed that like these simpler plant genomes, 24-nt siRNAs whose abundance differs between maize parents also show a trend of downregulation following hybridization. Surprisingly, hybrid vigor is fully maintained when 24-nt siRNAs are globally reduced by mutation of the RNA-dependent RNA polymerase2 (RDR2) encoded by modifier of paramutation1 (mop1). We also discovered that 21-22nt siRNAs derived from a number of distinct retrotransposon families differentially accumulate between B73 and Mo17 as well as their hybrid. Thus, maize possesses a novel source of genetic variation for regulating both transposons and genes at a genomic scale, which may contribute to its high degree of observed heterosis.
2012-05-26 | GSE37411 | GEO
Project description:Maize earshoot is a metabolic sink espcially related to nitrogen metabolism. Studies on the transcriptomic and metabolic changes occuring in earshoot can provide interesting answers about the nitrogen metabolic potential of the maize variety under study. B73 X Mo17 is a model maize hybrid. Developing earshoots from this genotype grown at nitrogen-deficient and nitrogen-sufficient conditions were sampled, processed and analyzed through microarray technology.
2010-01-14 | GSE17932 | GEO
Project description:Microarray analysis of gene expression patterns in immature ear, seedling, and embryo tissues from the maize inbred lines B73 and Mo17 identified numerous genes with variable expression. Some genes had detectable expression in only one of the two inbreds; most of these genes were detected in the genomic DNA of both inbreds, indicating that the expression differences are likely caused by differential regulation rather than by differences in gene content. Gene expression was also monitored in the reciprocal F1 hybrids B73xMo17 and Mo17xB73. The reciprocal F1 hybrid lines did not display parental effects on gene expression levels. Approximately 80% of the differentially expressed genes displayed additive expression patterns in the hybrids relative to the inbred parents. The approximately 20% of genes that display nonadditive expression patterns tend to be expressed at levels within the parental range, with minimal evidence for novel expression levels greater than the high parent or less than the low parent. Analysis of allele-specific expression patterns in the hybrid suggested that intraspecific variation in gene expression levels is largely attributable to cis-regulatory variation in maize. Collectively, our data suggest that allelic cis-regulatory variation between B73 and Mo17 dictates maintenance of inbred allelic expression levels in the F1 hybrid, resulting in additive expression patterns. Keywords: genotype comparison
2007-06-21 | GSE8179 | GEO
Project description:Microarray analysis of gene expression patterns in immature ear, seedling, and embryo tissues from the maize inbred lines B73 and Mo17 identified numerous genes with variable expression. Some genes had detectable expression in only one of the two inbreds; most of these genes were detected in the genomic DNA of both inbreds, indicating that the expression differences are likely caused by differential regulation rather than by differences in gene content. Gene expression was also monitored in the reciprocal F1 hybrids B73xMo17 and Mo17xB73. The reciprocal F1 hybrid lines did not display parental effects on gene expression levels. Approximately 80% of the differentially expressed genes displayed additive expression patterns in the hybrids relative to the inbred parents. The approximately 20% of genes that display nonadditive expression patterns tend to be expressed at levels within the parental range, with minimal evidence for novel expression levels greater than the high parent or less than the low parent. Analysis of allele-specific expression patterns in the hybrid suggested that intraspecific variation in gene expression levels is largely attributable to cis-regulatory variation in maize. Collectively, our data suggest that allelic cis-regulatory variation between B73 and Mo17 dictates maintenance of inbred allelic expression levels in the F1 hybrid, resulting in additive expression patterns. Keywords: genotype comparison
2007-06-21 | GSE8176 | GEO