Messenger RNA abundance and lifetime: a correlation in Drosophila cells but not in HeLa

Messenger RNA in eukaryotes is comprised of several abundance classes. Also, the decay of these unstable molecules shows at least two very different lifetimes. Two independent techniques are used here to examine the relation between message abundance and lifetime in cell lines from very different organisms. The methods give consistent results for each cell line; however, the two cell types show very different results. In brosophile cells, slowly decaying sequences fall in the abundant class while scarce sequences turn over rapidly. In contrast, in HeLa cells the abundant and scarce message classes are each comprised of long- and short-lived molecules.