Function of Tissue-specific eIF4E isoforms in Caenorhabditis elegans

East Carolina University, Greenville NC

Investigators

Abstract

The critical question in embryonic development is, "How do nondescript (undifferentiated) cells change in character to become the very specialized cells that make up the vital organs of a fetus?". It is already known that the production of new and unique proteins in individual cells very early in embryo development contributes to their taking on the character of adult tissue types. Processes that introduce (synthesize) new proteins ultimately direct cells to form distinct organ systems such as brain, muscle, gonad and gut. It is this regulation of new protein synthesis in embryos that is the focus of this research. The soil-dwelling nematode worm, Caenorhabditis elegans, develops from a fertilized egg to an organized multicellular embryo in a manner very similar to that of higher animals. Fortunately these worms have a far simpler body plan made up of just a few muscles, neurons, digestive and reproductive organs. They also grow to adulthood in just one day. More to the point, the critical genes and gene products expressed at the earliest stages of development are very similar in this simple model system. Among these products are messenger RNAs (mRNA) that are stored in egg or embryo. These mRNAs are recruited to ribosomes (the protein synthesizing machines of the cell) at just the right moment to be used as a template for the synthesis of regulatory or structural proteins. The mRNA recruiting factors have been studied for many years, and were thought to be identical in every type of cell in the body. However, Dr. Keiper's laboratory has recently shown that unique forms (isoforms) of these factors are found in certain tissue types, most notably those that are undergoing developmental changes in embryos. The current project addresses the role of specialized protein synthesis factors in selecting which mRNAs are used in embryonic cells. An understanding of their unique activities will begin to uncover how different cells begin to express a unique set of proteins. This cell-specific translational control is part of the internal program that takes embryos from a uniform mass of cells to a complex adult organism. Students and postdoctoral researchers involved in this project will learn how informational biomolecules (DNA, RNA and protein) elaborate the changes that make embryogenesis a fascinating dynamic process.