Project description:Genes are generally thought to be expressed from both alleles. There are some exceptions, including Random monoallelic expression (RME), even though its extent is still somewhat debated. We assessed whether and how some autosomal genes that we previously identified as being RME are prone to persistent and stable monoallelic expression. Not only do we confirm the occurrence of RME at large frequencies, our results also reveal unforeseen modes of allelic expression,that appear to be gene specific and epigenetically regulated. This non-canonical allelic regulation has large physiological and pathological implications and represents novel therapeutic perspectives.
Project description:We perform a systematic classification of allelic imbalance in mouse hybrids derived from reciprocal crosses of divergent strains. We observe that deviation from balanced biallelic expression is common, occurring in ~20% of the mouse transcriptome. Allelic imbalance attributed to genotype is by far the most prevalent class and typically is tissue-specific. However, some genotype-based imbalance is maintained across tissues and is associated with greater genetic variation, especially in 5’ and 3’ termini of transcripts. We further identify novel random monoallelic and imprinted genes, and find that genotype can compete with parental origin even in the setting of large imprinted regions. PolyA-selected RNA-sequencing in F1 hybrid and parental cells of Mm. musculus and Mm. castaneus origin
Project description:We perform a systematic classification of allelic imbalance in mouse hybrids derived from reciprocal crosses of divergent strains. We observe that deviation from balanced biallelic expression is common, occurring in ~20% of the mouse transcriptome. Allelic imbalance attributed to genotype is by far the most prevalent class and typically is tissue-specific. However, some genotype-based imbalance is maintained across tissues and is associated with greater genetic variation, especially in 5’ and 3’ termini of transcripts. We further identify novel random monoallelic and imprinted genes, and find that genotype can compete with parental origin even in the setting of large imprinted regions.
Project description:The diploid fungal pathogen Candida albicans is a highly heterozygous organism, with numerous non-synonymous substitutions often seen within two alleles. RNA-sequencing of the wild-type strain SC5314 has revealed 233 genes with significant levels of allelic expression imbalance. Overall percentage protein identity comparisons were significantly lower in these differentially expressed alleles. This suggests that two different, perhaps functionally divergent, proteins are being expressed at significantly different quantities by the two alleles of a single gene. Previously, gene expression levels have been correlated with structural factors such as GC content, ORF length and codon usage. Here, these factors were first correlated with overall gene expression data to decipher the relationship they have with gene expression in Candida albicans. These relationships were then used to assess the contribution of these factors to allelic expression imbalance. GC content and codon usage did not differ significantly in differentially expressed alleles whereas ORF length was found to be significantly lower in the allele with lowest expression. This surprising result goes against the overall trend observed between length and gene expression. Differences in GC content and ORF length between alleles correlated strongly with percentage protein identity, suggesting an indirect link between these factors and allelic expression imbalance. One sample (SC5314: wild-type strain) assessed in triplicate and compared to the reference diploid genome
Project description:The diploid fungal pathogen Candida albicans is a highly heterozygous organism, with numerous non-synonymous substitutions often seen within two alleles. RNA-sequencing of the wild-type strain SC5314 has revealed 233 genes with significant levels of allelic expression imbalance. Overall percentage protein identity comparisons were significantly lower in these differentially expressed alleles. This suggests that two different, perhaps functionally divergent, proteins are being expressed at significantly different quantities by the two alleles of a single gene. Previously, gene expression levels have been correlated with structural factors such as GC content, ORF length and codon usage. Here, these factors were first correlated with overall gene expression data to decipher the relationship they have with gene expression in Candida albicans. These relationships were then used to assess the contribution of these factors to allelic expression imbalance. GC content and codon usage did not differ significantly in differentially expressed alleles whereas ORF length was found to be significantly lower in the allele with lowest expression. This surprising result goes against the overall trend observed between length and gene expression. Differences in GC content and ORF length between alleles correlated strongly with percentage protein identity, suggesting an indirect link between these factors and allelic expression imbalance.