Cell division is a complex dance where new daughter cells inherit a mix of helpful and potentially harmful molecules from their mother cells. A recent study by the Max Planck Institute sheds light on how daughter cells shield themselves from a hidden danger: ultraviolet (UV)-damaged RNA inherited from their sun-exposed mothers.
While sunlight brings warmth, its UV rays pose a threat, damaging not only DNA but also RNA, another crucial molecule. Researchers observed a protein called DHX9 clumping into structures within cells after UV exposure.
"Finding this protein forming droplets outside the nucleus was like finding a snowball in the desert," says Asifa Akhtar, Director at the MPI.
Initially, scientists thought these DHX9 granules protected against DNA damage. However, further investigation revealed a surprising truth: these granules were packed with UV-damaged RNA.
"We discovered an elegant mechanism where cells trap harmful UV-damaged RNA using DHX9 granules," explains Akhtar. This essentially quarantines the damage, preventing it from causing further problems within the cell.
But the story takes another twist. Researchers noticed that cells with these DHX9 granules always appeared in pairs, suggesting they formed not in the mother cell, but in the daughter cells after division! Live cell imaging confirmed this, showing DHX9 normally residing in the nucleus before gathering into droplets in the daughter cell's cytoplasm.
Preventing DHX9 granule formation in daughter cells proved fatal, highlighting their crucial role in safeguarding against inherited RNA damage. "This process is like wiping the slate clean for the daughter cell," says Akhtar.
Understanding this mechanism not only deepens our knowledge of the cell cycle but also opens doors for medical research. Sunburn, neurodegenerative diseases, and cancer are linked to RNA imbalances and cell cycle disruptions.
"By understanding how new cells recognize and eliminate damaged RNA, we could potentially develop new treatments for diseases linked to RNA mismanagement," concludes Akhtar.
0 Comments