'Messenger RNA' in a fission yeast.

Abstract

IT is now widely believed that one fraction of the ribonucleic acid (RNA) of a cell, the ‘messenger RNA’, is responsible for the transmission of genetic information from the deoxyribonucleic acid (DNA) of the nucleus to the cytoplasm1. This messenger RNA has been identified with that fraction of the total RNA which shows some or all of the following properties: a high rate of turn-over, a physical difference from the ribosomal RNA, a base composition similar to the DNA, and a capacity to interact specifically with the DNA. Evidence for the existence of this RNA has come from phage-infected bacteria2,3, normally growing bacteria3, and mammalian nuclei4,5. It has also come from bacteria6 and budding yeast7 in a ‘step-down’, where growing cells are transferred from a rich medium to a poor one. For a period after the step-down it seems that messenger RNA is the main kind of RNA made by the cells. We have investigated this situation in the fission yeast Schizosaccharomyces pombe with the object both of identifying messenger RNA and also of following by autoradiography its location in the cell and its relation to the cell-cycle.