2 research outputs found
Cerebral organoids derived from Sandhoff disease-induced pluripotent stem cells exhibit impaired neurodifferentiation
Sandhoff disease, one of the GM2 gangliosidoses, is a lysosomal storage disorder characterized by the absence of beta-hexosaminidase A and B activity and the concomitant lysosomal accumulation of its substrate, GM2 ganglioside. It features catastrophic neurodegeneration and death in early childhood. How the lysosomal accumulation of ganglioside might affect the early development of the nervous system is not understood. Recently, cerebral organoids derived from induced pluripotent stem (iPS) cells have illuminated early developmental events altered by disease processes. To develop an early neurodevelopmental model of Sandhoff disease, we first generated iPS cells from the fibroblasts of an infantile Sandhoff disease patient, then corrected one of the mutant HEXB alleles in those iPS cells using CRISPR/Cas9 genome-editing technology, thereby creating isogenic controls. Next, we used the parental Sandhoff disease iPS cells and isogenic HEXB-corrected iPS cell clones to generate cerebral organoids that modeled the first trimester of neurodevelopment. The Sandhoff disease organoids, but not the HEXB-corrected organoids, accumulated GM2 ganglioside and exhibited increased size and cellular proliferation compared with the HEXB-corrected organoids. Whole-transcriptome analysis demonstrated that development was impaired in the Sandhoff disease organoids, suggesting that alterations in neuronal differentiation may occur during early development in the GM2 gangliosidoses
Packaged and Free Satellite Tobacco Mosaic Virus (STMV) RNA Genomes Adopt Distinct Conformational States
The RNA genomes of viruses likely
undergo multiple functionally
important conformational changes during their replication cycles,
changes that are poorly understood at present. We used two complementary
in-solution RNA structure probing strategies (SHAPE-MaP and RING-MaP)
to examine the structure of the RNA genome of satellite tobacco mosaic
virus inside authentic virions and in a capsid-free state. Both RNA
states feature similar three-domain architectures in which each major
replicative functiontranslation, capsid coding, and genome
synthesisfall into distinct domains. There are, however, large
conformational differences between the in-virion and capsid-free states,
primarily in one arm of the central T domain. These data support a
model in which the packaged capsid-bound RNA is constrained in a local
high-energy conformation by the native capsid shell. The removal of
the viral capsid then allows the RNA genome to relax into a more thermodynamically
stable conformation. The RNA architecture of the central T domain
thus likely changes during capsid assembly and disassembly and may
play a role in genome packaging