Project description:We describe circadian clock-dependent changes in ribosome composition in Neurospora crassa depending on cell type, stress, or developmental state. Mass spectrometry of ribosomes isolated at different circadian times identified six ribosomal proteins and one ribosome-associated protein with clock-controlled abundance. We confirmed clock control of eL31-HA abundance in purified ribosomes and found that deletion of eL31 altered and inhibited translation rhythms. We examined ribosome protected footprint (RPF)-seq reads mapping past stop codons over circadian time to reveal clock-dependent and eL31-enhanced rhythms in translation termination fidelity. We discovered that eL31 promotes proper ion homeostasis and translation elongation fidelity, and demonstrated that the circadian clock governs daily changes in ribosome composition that control rhythms in translation and impact translation fidelity, likely through changes in intracellular Mg2+ levels.
Project description:Introgressed variants from other species can be an important source of genetic variation because they may arise rapidly, can include multiple mutations on a single haplotype, and have often been pretested by selection in the species of origin. Although introgressed alleles are generally deleterious, several studies have reported introgression as the source of adaptive alleles-including the rodenticide-resistant variant of Vkorc1 that introgressed from Mus spretus into European populations of Mus musculus domesticus. Here, we conducted bidirectional genome scans to characterize introgressed regions into one wild population of M. spretus from Spain and three wild populations of M. m. domesticus from France, Germany, and Iran. Despite the fact that these species show considerable intrinsic postzygotic reproductive isolation, introgression was observed in all individuals, including in the M. musculus reference genome (GRCm38). Mus spretus individuals had a greater proportion of introgression compared with M. m. domesticus, and within M. m. domesticus, the proportion of introgression decreased with geographic distance from the area of sympatry. Introgression was observed on all autosomes for both species, but not on the X-chromosome in M. m. domesticus, consistent with known X-linked hybrid sterility and inviability genes that have been mapped to the M. spretus X-chromosome. Tract lengths were generally short with a few outliers of up to 2.7 Mb. Interestingly, the longest introgressed tracts were in olfactory receptor regions, and introgressed tracts were significantly enriched for olfactory receptor genes in both species, suggesting that introgression may be a source of functional novelty even between species with high barriers to gene flow.
Project description:Ribosome composition can vary depending on cell type, stress or developmental state. Here we describe circadian clock-dependent changes in ribosome composition in Neurospora crassa. Mass spectrometry of ribosomes isolated at different circadian times identified six ribosomal proteins and one ribosome-associated protein with clock-controlled abundance. We confirmed clock control of eL31-HA abundance in purified ribosomes and found that deletion of eL31 altered translation of many mRNAs and inhibited translation rhythms for 42% of rhythmically translated mRNAs. Because eL31 homologs promote translation termination fidelity, we examined ribosome protected footprint (RPF)-seq reads mapping past stop codons over circadian time to reveal clock-dependent and eL31-enhanced rhythms in translation termination fidelity. We further discovered that eL31 promotes proper ion homeostasis and translation elongation fidelity. Taken together these studies demonstrated that the circadian clock governs daily changes in ribosome composition that control rhythms in translation and impact translation fidelity, likely through changes in intracellular Mg2+ levels.
Project description:Ribosome composition can vary depending on cell type, stress or developmental state. Here we describe circadian clock-dependent changes in ribosome composition in Neurospora crassa. Mass spectrometry of ribosomes isolated at different circadian times identified six ribosomal proteins and one ribosome-associated protein with clock-controlled abundance. We confirmed clock control of eL31-HA abundance in purified ribosomes and found that deletion of eL31 altered translation of many mRNAs and inhibited translation rhythms for 42% of rhythmically translated mRNAs. Because eL31 homologs promote translation termination fidelity, we examined ribosome protected footprint (RPF)-seq reads mapping past stop codons over circadian time to reveal clock-dependent and eL31-enhanced rhythms in translation termination fidelity. We further discovered that eL31 promotes proper ion homeostasis and translation elongation fidelity. Taken together these studies demonstrated that the circadian clock governs daily changes in ribosome composition that control rhythms in translation and impact translation fidelity, likely through changes in intracellular Mg2+ levels.
Project description:Nuclear receptor subfamily 1 group D member 1 (NR1D1), also known as Rev-Erbα, is a circadian clock component that functions as a transcriptional repressor which coordinates circadian rhythm and cell metabolism. Altered circadian clock characteristics have been shown in malignant thyroid neoplasms, and NR1D1 is one of the recurrence-associated genes in papillary thyroid cancer. We aimed to investigate the biological role of NR1D1 in thyroid cancer cells.