Noteworthy
When it comes to intracellular pathogens, we usually think of those that remain inside a membrane-enclosed vacuole and those that escape into the cytoplasm. Much rarer are cases of parasite that make a living inside the nucleus. Makes sense, entering the space where the DNA resides is likely counterproductive as it could easily trigger apoptosis (programmed cell death). Fast death of the infected host cell would serve to limit the infection. But, perhaps not surprisingly, some bacteria have found the way to make a living in the nucleus.
One such clever nuclear invader infects mussels that resides in the vicinity deep ocean vents and is known as "Ca. Endonucleobacter" (Ca. since it has yet to be cultured.) In a recent publication the authors show just how a single cell that reaches the nucleus can lead to >80,000 progeny cells before causing major nuclear damage. It's secret? It doesn't even try to eat the DNA or RNA. Rather, it express importers for nutrients such as sugars, lipids, amino acids and mucin. And it secretes apoptosis inhibitors! Strikingly, the genes that encode these inhibitors in the bacterium originally came from the host, via eukaryote-to-bacteria horizontal gene transfer. You should dive deep into this fascinating paper. (See the paper for figure explanation.)
Our 2018 piece The Nuclear Option mentioned "Ca. Endonucleobacter" already, besides other bacteria that pursue this unusual lifestyle.
("Noteworthy" is the new format for STC's Thursday posts. Please read our Jan 20, 2025 post outlining this and other changes in our blog.)
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