Translational inhibition in mitotic HeLa cells.

Abstract

Studies of mitotic HeLa cells in an in vitro system reveal that ribosomes from metaphase or metaphase-arrest cells constitute the rate-limiting component in amino acid incorporation, the relative rates of protein synthesis stimulated by ribosomes from interphase and mitotic cells, respectively, reflects precisely the rates observed in vivo, the coating of ribosomes with a trypsin-sensi-tive material, presumably derived from the nucleus upon dissolution of the nuclear membrane at mitosis, is responsible for the observed translational inhibition, and almost full activity can be restored to these coated ribosomes with gentle trypsin treatment which is thought to remove an inhibitor bound to the ribosomal surface. The possible role of nuclear histones as a translational inhibitor (repressor?) is considered, and an explanation offered for the previously observed inhibition of viral synthesis in the metaphase-arrest cell.