2025/12/22 by Nidhi Parikh, S.C. Penna, Eliza Neal +1 · 1 voice
Biochemistry, Genetics and Molecular Biology · Medicine · #ATP Synthase and ATPases Research #GDF15 and Related Biomarkers #Mitochondrial Function and Pathology
paper · pdf · doi:10.64898/2025.12.19.694874
openalex publication_date 2025/12/22 · openalex created_date 2025/12/23 · openalex updated_date 2026/07/14
The spatiotemporal organization of multiple components within biomolecular condensates helps coordinate gene expression. Mitochondria separate transcription and RNA processing into two distinct condensates: mt-nucleoids and mtRNA granules (MRGs), respectively. However, how mtRNA transcripts are transferred from mt-nucleoids to distant MRGs was unclear. With high-resolution imaging, we examined the steady-state organization of mt-condensates in human cells. We identified a wide distribution of distances between centroids of mt-condensates, from roughly a micron apart to within 100 nm of each other. Live imaging revealed that such organization was dynamic: mt-condensates frequently underwent cycles of mixing and demixing. Indeed, mtRNA transcripts and the mtRNA polymerase co-localized within mixed mt-condensates, while transcription inhibition led to complete dissolution of MRGs, supporting that nascently transcribed mtRNA is a key driver of mt-condensate organization. Together, our results show that active transcription sustains the phase coexistence between mt-nucleoids and MRGs, with implications for transcriptional condensates more broadly.