[
Genetics,
2017]
The Genetics Society of America's Edward Novitski Prize recognizes a single experimental accomplishment or a body of work in which an exceptional level of creativity and intellectual ingenuity has been used to design and execute scientific experiments to solve a difficult problem in genetics. The 2017 winner, Jonathan Hodgkin, used elegant genetic studies to unravel the sex determination pathway in Caenorhabditis elegans He inferred the order of genes in the pathway and their modes of regulation using epistasis analyses-a powerful tool that was quickly adopted by other researchers. He expanded the number and use of informational suppressor mutants in C. elegans that are able to act on many genes. He also introduced the use of collections of wild C. elegans to study naturally occurring genetic variation, paving the way for SNP mapping and QTL analysis, as well as studies of hybrid incompatibilities between worm species. His current work focuses on nematode-bacterial interactions and innate immunity.
[
Development,
1997]
Early embryonic germ cells in C. elegans and D. melanogaster fail to express many messenger RNAs expressed in somatic cells. In contrast, we find that ribosomal RNAs are expressed in both cell types. We show that this deficiency in mRNA production correlates with the absence of a specific phosphoepitope on the carboxy-terminal domain of RNA polymerase II. In both C. elegans and Drosophila embryos, this phosphoepitope appears in somatic nuclei coincident with the onset of embryonic transcription, but remains absent from germ cells until these cells associate with the gut primordium during gastrulation. In contrast, a second distinct RNA polymerase II phosphoepitope is present continuously in both somatic and germ cells. The germ-line-specific factor PIE-1 is required to block mRNA production in the germ lineage of early C. elegans embryos (Seydoux, G., Mello, C. C., Pettitt, J., Wood, W. B., Priess, J. R. and Fire, A. (1996) Nature 382, 713-716). We show here that PIE-1 is also required for the germ-line-specific pattern of RNA polymerase II phosphorylation. These observations link inhibition of mRNA production in embryonic germ cells to a specific modification in the phosphorylation pattern of RNA polymerase II and suggest that repression of RNA polymerase II activity may be part of an evolutionarily conserved mechanism that distinguishes germ line from soma during early embryogenesis. In addition, these studies also suggest that different phosphorylated isoforms of RNA polymerase II perform distinct functions.