Advanced Imaging Reveals Internal Structure of PML Bodies, Nuclear Compartments Involved in DNA Maintenance
Researchers used cryo-electron tomography and advanced microscopy to visualize the internal molecular organization of PML bodies, membrane-less compartments in cell nuclei. The study found that PML bodies contain a protein shell surrounding a porous core with organized chromatin structures, protein complexes, and proteasomes. This structural insight may explain how PML bodies selectively regulate DNA maintenance and damage responses.
Scientists employed cryo-correlative light and electron microscopy (cryo-CLEM) to directly visualize PML bodies within intact cell nuclei at high resolution. The imaging revealed that PML bodies consist of a diffuse protein shell enclosing an inner core with a porous architecture. Within this core, researchers identified nucleosomes arranged in columnar trinucleosome assemblies, along with TRiC chaperonin complexes in multiple conformational states, PA28 proteasomes, and membrane structures of unknown function. The porous interior architecture suggests PML bodies may function similarly to size-exclusion chromatography, selectively allowing certain molecules to enter while excluding others based on physical size. These findings provide the first high-resolution structural characterization of PML bodies and identify their functional components, advancing understanding of how these nuclear compartments regulate telomere maintenance and DNA damage responses.
Limitations & open questions
The study does not discuss potential functional implications of the membrane structures detected within PML bodies, which are noted as being of unknown function. Additionally, the mechanisms by which the size-exclusion model proposed for PML bodies might be regulated or modulated in response to cellular stress are not addressed.
What different sources said
- bioRxivCenter
In situ molecular architecture of PML bodies reveals open-state columnar trinucleosome assemblies within a porous, chromatin-permissive interior
Related
Profilin-1 Deficiency Activates Immune Response Against Breast Cancer in Preclinical Study
Researchers found that removing the Profilin-1 protein from breast cancer cells triggers DNA damage and activates an immune pathway called STING, which recruits cancer-fighting T cells and causes tumor regression in mice. The study used CRISPR gene-editing technology to deplete Profilin-1 and observed that the resulting genomic instability paradoxically strengthens anti-tumor immunity. The findings suggest targeting Profilin-1 could be a new strategy to enhance immunotherapy effectiveness in breast cancer.
Computational Study Explores How Magnetic Fields May Affect Tomato Plant Ion Channels
Researchers used molecular dynamics simulations to investigate how static magnetic fields affect the CNGC6 ion channel in tomato plants, finding that magnetic fields may alter the channel's structure in specific ways. The study was motivated by observations that magnetic treatment of tomato seeds appears to speed germination and improve plant development, though the underlying cellular mechanisms remain unclear. The findings provide a computational foundation for future experimental work, though the authors emphasize this is a preliminary exploratory study requiring validation.
New Algorithm Simplifies Evolutionary Network Reconstruction for Hybridized Species
Researchers developed NetCS, a fast algorithm for reconstructing evolutionary networks in hybridized species that avoids expensive computational bottlenecks. The method works well when given accurate intermediate data but reveals that the real challenge in network inference lies in an earlier reconstruction step. This finding could enable phylogenetic analyses of larger datasets while identifying where future improvements are needed.