Differential inhibitory effect of 5-fluorouridine on RNA labelling in dipteran salivary gland cells

In Chironomus salivary glands, 5-fluorouridine inhibits labelling of ribosomal RNA. The drug does not prevent labelling of other types of RNA- like heterodisperse messenger-like RNA, 75-S RNA of Balbiani ring origin and 4-S RNA, which furthermore are exported to cytoplasm. The potential use of this drug for the study of RNA metabolism in insect salivary glands can be compared with the use of low doses of actinomycin D in cultured mammalian cells.