Translational control by the 3'untranslated regions (3'UTRs) of mRNAs contributes to important events throughout the development of C. elegans. In oocytes and early embryos, maternal mRNAs are controlled by 3'UTR elements to restrict translation of their protein products to specific blastomeres. Localized translation is probably critical for specifying blastomere identity. In both germline and somatic cells, mRNAs from sex determining genes are translationally repressed by 3'UTR controls. These controls balance the activities that specify male and female cell fates. During larval development, the temporal sequence of cell lineages requires 3'UTR-mediated regulation of heterochronic genes by a small non-protein coding RNA. We review what is known about these translational control mechanisms in C. elegans. This overview illustrates that translational control by 3'UTR elements is a powerful mechanism for regulating the expression of multiple gene products in diverse cell types during development of a multi-cellular animal.

Copyright 1997 Academic Press Limited.