Long thought to simply assemble cellular proteins from RNA molecules, ribosomes may also control the expression of key development genes.

Maria Barna at the University of California, San Francisco, and her team discovered that mouse strains with short, kinked tails (pictured) and an extra rib are deficient in a protein called RPL38 — one of the dozens that make up the ribosome. The defect seems to limit the production of some Hox proteins, which help to form the body plan. In normal mouse embryos, RPL38 is expressed at its highest levels in tissues in which the short-tailed mutants show defects, such as the vertebrae. Moreover, the expression of many of the ribosome's 79 constituent proteins varied widely from tissue to tissue in these embryos, suggesting that ribosomes may have specialized functions.

Credit: M. BARNA

Cell 145, 383–397 (2011)