Project description:Robertsonian chromosomes are a type of variant chromosome found commonly in nature. Present in one in 800 humans, these chromosomes can underlie infertility, trisomies, and increased cancer incidence. Recognized cytogenetically for more than a century, their origins have remained mysterious. Recent advances in genomics allowed us to assemble three human Robertsonian chromosomes completely. We identify a common breakpoint and epigenetic changes in centromeres that provide insight into the formation and propagation of common Robertsonian translocations. Further investigation of the assembled genomes of chimpanzee and bonobo highlights the structural features of the human genome that uniquely enable the specific crossover event that creates these chromosomes. Resolving the structure and epigenetic features of human Robertsonian chromosomes at a molecular level paves the way to understanding how chromosomal structural variation occurs more generally, and how chromosomes evolve.
Project description:Purpose: determine if gH2AX and H3.3 are enriched at unsynapsed regions of chromosomes involved in translocations in mouse germ line (meiotic prophase I) Methods: testes were isolated from 4-week or 6-week old heterozygous carriers of a single Robertsonian translocation RB(8;12) or 3 Robertsonian translocations RB(8;12), RB(1;3) and RB(9;14) and controls. ChIP assays were conducted as described in Smagulova 2011. Experiments done in triplicate. Results: We find enrichment of gH2AX in the proximal gene-rich regions of translocation-associated chromosomes and reduced enrichment of gH2AX and H3.3 at sex chromosomes
Project description:Rho-associated coiled-coil kinase (ROCK) protein is a central kinase that regulates numerous cellular functions, including cellular polarity, motility, proliferation and apoptosis. Here, we demonstrate that ROCK has antiviral properties and inhibition of its activity results in enhanced propagation of human cytomegalovirus (HCMV). We show that during HCMV infection ROCK1 translocates to the nucleus and concentrates in the nucleolus were it co-localizes with the stress related chaperone, heat shock cognate 71 kDa protein (Hsc70) . Gene expression measurements showed that inhibition of ROCK activity does not affect the cellular stress response. We further demonstrate that inhibition of myosin, one of the central targets of ROCK, also increases HCMV propagation, implying that the anti-viral activity of ROCK might be mediated by activation of the actomyosin network. Finally, we demonstrate that inhibition of ROCK results in increased levels of the tegument protein UL32 and of viral DNA in the cytoplasm, suggesting ROCK activity hinders the efficient egress of HCMV particles out of the nucleus. Altogether our findings illustrate ROCK activity restricts HCMV propagation and suggest this inhibitory effect may be mediated by suppression of capsid egress out of the nucleus.
Project description:Tauopathies are age-associated neurodegenerative diseases whose mechanistic underpinnings remain elusive, partially due to lack of appropriate human models. Here, we engineered new human induced pluripotent stem cell (hiPSC)-derived neuronal lines to express 4R Tau and 4R Tau carrying the P301S MAPT mutation when differentiated into neurons. 4R-P301S neurons display progressive Tau inclusions upon seeding with Tau fibrils and recapitulate features of tauopathy phenotypes including shared transcriptomic signatures, autophagic body accumulation, and reduced neuronal activity. A CRISPRi screen of genes associated with Tau pathobiology identified over 500 genetic modifiers of seeding-induced Tau propagation, including retromer VPS29 and genes in the UFMylation cascade. In progressive supranuclear palsy (PSP) and Alzheimer’s Disease (AD) brains, the UFMylation cascade is altered in neurofibrillary-tangle-bearing neurons. Inhibiting the UFMylation cascade in vitro and in vivo suppressed seeding-induced Tau propagation. This model provides a robust platform to identify novel therapeutic strategies for 4R tauopathy.