Attention cell biologists: think that you know all cell components? Nucleus? Nucleolus? Basic stuff, right?
Now how about this: nucleolinus. If you never heard of it, you'd be excused - the nucleolinus is a structured that was discovered and forgotten long ago. Until scientists at the Marine Biological Laboratory's Jospehine Bay Paul Center re-discovered it:
"We've known for a long time that there are elements in the cytoplasm that need to be assembled for the cell to divide," Mark Alliegro says. "But this tells us that elements in the cytoplasm and in the nucleus have to join together to make the apparatus that separates chromosomes [an important part of cell division]."
This function of the nucleolinus, which is closely associated with a structure called the nucleolus, could clarify recent studies indicating an important role for the nucleolus in cell division. "When people talk about the nucleolus playing a direct role in cell cycle regulation, it may very well be that it's the nucleolinus," Mark Alliegro says.
Mark Alliegro and his colleagues speculate that the nucleolinus may be responsible for recruiting proteins required by centrosomes, which have long been known to play an important role in cell division. "What we're doing now is attempting to answer some functional questions about the nucleolinus in Spisula cells," he says. "But we're also moving it into other systems that are easier to experiment in." They are planning to study the role of the nucleolinus in mammalian cells.