Project description:Many loci in the human genome harbor complex genomic structures that can result in susceptibility to genomic rearrangements leading to various genomic disorders. Nephronophthisis 1 (NPHP1, MIM# 256100) is an autosomal recessive disorder that can be caused by defects of NPHP1; the gene maps within the human 2q13 region where low copy repeats (LCRs) are abundant. Loss of function of NPHP1 is responsible for approximately 85% of the NPHP1 cases - about 80% of such individuals carry a large recurrent homozygous NPHP1 deletion that occurs via non-allelic homologous recombination (NAHR) between two flanking directly oriented ~45 kb LCRs. Published data revealed a non-pathogenic inversion polymorphism involving the NPHP1 gene flanked by two inverted ~358 kb LCRs. Using optical mapping and array-comparative genomic hybridization, we identified three potential novel structural variant (SV) haplotypes at the NPHP1 locus that may protect a haploid genome from genomic instability and NPHP1 deletion. Inter-species comparative genomic analyses among primate genomes revealed massive genomic changes during evolution. The aggregated data suggest that dynamic genomic rearrangements occurred historically within the NPHP1 locus and generated SV haplotypes observed in the human population today, which may have differential susceptibility to the NPHP1 deletion within a personal genome. Our study documents diverse SV haplotypes at a complex LCR-laden human genomic region. Comparative analyses provide a model for how this complex region arose during primate evolution, and studies among humans reflect the possibility that intra-species polymorphism may potentially modulate an individual’s susceptibility to acquiring disease-associated alleles.
Project description:Embryonic development is largely conserved among mammals. However, certain genes show divergent functions. By generating a transcriptional atlas containing >30,000 cells from post-implantation non-human primate embryos, we uncover that ISL1, a gene with a well-established role in cardiogenesis, controls a gene regulatory network in primate amnion. CRISPR/Cas9-targeting of ISL1 results in non-human primate embryos which do not yield viable offspring, demonstrating that ISL1 is critically required in primate embryogenesis. On a cellular level, mutant ISL1 embryos display a failure in mesoderm formation due to reduced BMP4 signaling from the amnion. Via loss of function and rescue studies in human embryonic stem cells we confirm a similar role of ISL1 in human in vitro derived amnion. This study highlights the importance of the amnion as a signaling center during primate mesoderm formation and demonstrates the potential of in vitro primate model systems to dissect the genetics of early human embryonic development.
Project description:Key to the human brain’s unique capacities are a myriad of neural cell types, specialized molecular expression signatures, and complex patterns of neuronal connectivity. Neurons in the human brain communicate via well over a quadrillion synapses. Their specific contribution might be key to the dynamic activity patterns that underlie primate-specific cognitive function. Recently, functional differences were described in transmission capabilities of human and rat synapses. To test whether unique expression signatures of synaptic proteins are at the basis of this, we performed a quantitative analysis of the hippocampal synaptic proteome of four mammalian species, two primates, human and marmoset, and two rodents, rat and mouse. Abundance differences down to 1.15-fold at an FDR-corrected p-value of 0.005 were reliably detected using SWATH mass spectrometry. The high measurement accuracy of SWATH allowed the detection of a large group of differentially expressed proteins between individual species and rodent versus primate. Differentially expressed proteins between rodent and primate were found highly enriched for plasticity-related proteins.
Project description:We produced an extensive transcript catalog for LCLs of 5 primate species by leveraging isoform sequencing and short-read RNA-seq. The curated transcriptomes were used to assist mass spectrometry protein identifications.
Project description:Molecular characterization of the individual neuron types existing in the primate dorsal root ganglion and the relation to model organisms used for studying somatosensation and pain is critical for understanding the cellular origin of chronic pain and for translational aspects of biomedical research. However, molecular insights into the primate dorsal root ganglion are missing and a systematic comparison of strategies for somatosensation between the mouse and primates is lacking. Here we classify non-human primate sensory neurons based on their transcriptome and identify neuronal types with heritability to chronic pain. We identify nine neuronal types and use machine learning to expose an overall cross-species conserved strategy and shared taxonomy for nociception, although with differences at individual gene level, highlighting the importance of incorporating primate knowledge for the successful translation of discoveries in rodent model organisms. Genomic loci implicated in chronic pain were mapped onto specific primate sensory neuron types to identify the cellular origin of chronic pain. The common-variant genome-wide association results for chronic pain point to the same cells at the same pain sites and concentrate on two different neuronal types between pain disorders, suggesting that causative cell types and molecular mechanisms are different between different pain conditions.
Project description:Alternative splicing (AS) influences the expression of human genes in diverse ways. We previously used subcellular fraction-sequencing (Frac-Seq) to reveal an unexpected connection between alternative splicing and isoform-specific mRNA translation. Here we apply comparative transcriptomics to explore alternative splicing coupled translational control (AS-TC) across 13 million years of primate evolution. We used Frac-seq to identify polyribosome associated mRNA isoforms from human, chimpanzee and orangutan induced pluripotent stem cell lines. We discovered orthologous AS-TC events with either conserved or species-specific translation patterns. Exons sequences associated with similar sedimentation profiles between species show strong sequence conservation compared to orthologous exons with divergent sedimentation profiles, suggesting exonic cis-regulatory elements influence to translational control. To test this hypothesis we created luciferase reporters from orthologous exons with divergent sedimentation profiles differing by a single nucleotide. Remarkably, single nucleotide substitutions were sufficient to drive species-specific expression of luciferase reporters. Together these data establish that cis-acting elements regulate AS-TC across primate species.