ABSTRACT: Natural epigenetic polymorphisms lead to intraspecific variation in Arabidopsis gene imprinting: allele specific mRNA-seq expression profiling in Arabidopsis thaliana Col, Ler, and Cvi parental and reciprocal F1 hybrid embryo and endosperm
Project description:Imprinted gene expression occurs during seed development in plants and is closely tied to differential DNA methylation of maternal and paternal alleles, particularly at proximal transposable elements (TEs). Since the epigenetic modification of TEs can vary within species, we investigated intraspecific variation in imprinting, coupled with analysis of DNA methylation and small RNAs, among three strains of Arabidopsis that display diverse seed size phenotypes. Unexpectedly we found that one strain, Cvi, is globally CG hypomethylated. We discovered three examples of strain-specific imprinting caused by epigenetic variation at a TE. Our data allowed us to predict and experimentally validate an instances of allele-specific imprinting in additional strains based only on methylation patterns. We conclude that numerous differences in imprinting can evolve in highly similar, recently diverged genotypes due to epiallelic variation present within the species. Our data demonstrate that epiallelic variation and genomic imprinting intersect to produce novel gene expression patterns in seeds. Examination of parent-of-origin specific and total gene expression in embryo, endosperm, and whole seeds. Samples with the same heading are biological replicates (e.g. CVN1, CVN2, and CVN3). High throughput Illumina sequencing of poly-A selected RNA from Arabidopsis Col, Ler and Cvi reciprocal F1 hybrid embryo and endosperm tissue isolated at 6 days after pollination to identify imprinted genes.
Project description:Natural epigenetic polymorphisms lead to intraspecific variation in Arabidopsis gene imprinting: BS-seq of Arabidopsis thaliana Col, Ler, and Cvi parental and reciprocal F1 hybrid embryo and endosperm
Project description:Natural epigenetic polymorphisms lead to intraspecific variation in Arabidopsis gene imprinting: small RNA-seq profiling in Arabidopsis thaliana Col, Ler, and Cvi parental and reciprocal F1 hybrid seeds
Project description:The contribution of epigenetic variation to phenotypic variation is unclear. Imprinted genes, because of their strong association with epigenetic modifications, represent an opportunity for the discovery of such phenomena. In mammals and flowering plants, a subset of genes are expressed from only one parental allele in a process called gene imprinting. Imprinting is associated with differential DNA methylation and chromatin modifications between parental alleles. In flowering plants imprinting occurs in endosperm seed tissue. Proper endosperm development is essential for the production of viable seeds. We previously showed that in Arabidopsis thaliana intraspecific imprinting variation is correlated with naturally occurring DNA methylation polymorphisms. Here, we investigated the mechanisms and function of allele-specific imprinting of the class IV homeodomain-Leucine zipper (HD-ZIP) transcription factor HDG3. In imprinted strains, HDG3 is expressed primarily from the methylated paternally inherited allele. We manipulated the methylation state of endogenous HDG3 in a non-imprinted strain and demonstrated that methylation of a proximal transposable element is sufficient to promote HDG3 expression and imprinting. Gain of HDG3 imprinting was associated with earlier endosperm cellularization. These results indicate that epigenetic variation alone is sufficient to explain imprinting variation and show that epialleles can underlie variation in seed development phenotypes.
Project description:Imprinted gene expression occurs during seed development in plants and is associated with differential DNA methylation of parental alleles, particularly at proximal transposable elements (TEs). Imprinting variability could contribute to observed parent-of-origin effects on seed development. We investigated intraspecific variation in imprinting, coupled with analysis of DNA methylation and small RNAs, among three Arabidopsis strains with diverse seed phenotypes. The majority of imprinted genes were parentally biased in the same manner among all strains. However, we identified several examples of allele-specific imprinting correlated with intraspecific epigenetic variation at a TE. We successfully predicted imprinting in additional strains based on methylation variability. We conclude that there is standing variation in imprinting even in recently diverged genotypes due to intraspecific epiallelic variation. These data demonstrate that epiallelic variation and genomic imprinting intersect to produce novel gene expression patterns in seeds. Whole genome bisulfite sequencing of embryo and endosperm (14 samples).
Project description:High throughput Illumina sequencing of poly-A selected RNA from Arabidopsis Col and Ler reciprocal F1 hybrid embryo and endosperm tissue isolated at 6-7 days after pollination to identify imprinted genes.
Project description:a2e_heterosis - cgh_colvscvi_wg - Arabidopsis thaliana accessions (Col-0, C24 and Cvi) and their hybrid were used to investigate the dynamics of the epigenome after intraspecific hybridization between - Comparative genome hybridization between Arabidopsis thaliana accessions Col-0 and CVi.
Project description:a2e_heterosis - h3k4me2_cvi - Arabidopsis thaliana accessions (Col-0, C24 and Cvi) and their hybrid were used to investigate the dynamics of the epigenome after intraspecific hybridization between - H3K4me2 profiling in Cvi
Project description:a2e_heterosis - h3k27me3_col(cvi) - Arabidopsis thaliana accessions (Col-0, C24 and Cvi) and their hybrid were used to investigate the dynamics of the epigenome after intraspecific hybridization between - H3K27me3 profiling in Col
