Originally published as Genetics Published Articles Ahead of Print on August 9, 2008.

Genetics, Vol. 179, 2001-2012, August 2008, Copyright © 2008
doi:10.1534/genetics.108.092197

Multiple Levels of Redundant Processes Inhibit Caenorhabditis elegans Vulval Cell Fates

Erik C. Andersen, Adam M. Saffer and H. Robert Horvitz1

Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139

1 Corresponding author: Department of Biology, Room 68-425, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, MA 02139.
E-mail: horvitz{at}mit.edu

Many mutations cause obvious abnormalities only when combined with other mutations. Such synthetic interactions can be the result of redundant gene functions. In Caenorhabditis elegans, the synthetic multivulva (synMuv) genes have been grouped into multiple classes that redundantly inhibit vulval cell fates. Animals with one or more mutations of the same class undergo wild-type vulval development, whereas animals with mutations of any two classes have a multivulva phenotype. By varying temperature and genetic background, we determined that mutations in most synMuv genes within a single synMuv class enhance each other. However, in a few cases no enhancement was observed. For example, mutations that affect an Mi2 homolog and a histone methyltransferase are of the same class and do not show enhancement. We suggest that such sets of genes function together in vivo and in at least some cases encode proteins that interact physically. The approach of genetic enhancement can be applied more broadly to identify potential protein complexes as well as redundant processes or pathways. Many synMuv genes are evolutionarily conserved, and the genetic relationships we have identified might define the functions not only of synMuv genes in C. elegans but also of their homologs in other organisms.


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Genetics 2008 179: NP. [Full Text]