60S ribosomes do not assemble without Yph1p (bottom).
Stillman/Elsevier
A protein found in DNA replication complexes is also essential for ribosome biosynthesis, according to new results from Yi-Chieh Du and Bruce Stillman (Cold Spring Harbor Laboratory, Cold Spring Harbor, NY). The findings imply that the biosynthesis of ribosomes is associated with the decision to enter the cell division cycle.
The authors identified proteins associated with the yeast origin recognition complex (ORC), a set of proteins that binds chromosomal origins of DNA replication. Among the proteins identified was Yph1p, a homologue of zebrafish pescadillo, mutations in which lead to cell proliferation defects. Yph1p was also found in complex with a variety of other proteins, including those involved in ribosome biogenesis, cell cycle regulation, and checkpoint control. “The first link to ribosome biosynthesis came from the finding of Erb1p in the Yph1p complex,” says Stillman. “Mutation of...
