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The Caenorhabditis elegans T-Box Factor MLS-1 Requires Groucho Co-Repressor Interaction for Uterine Muscle Specification

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posted on 17.08.2012 by Raymond R. Miller, Peter G. Okkema
T-box proteins are conserved transcription factors that play crucial roles in development of all metazoans; and, in humans, mutations affecting T-box genes are associated with a variety of congenital diseases and cancers. Despite the importance of this transcription factor family, very little is known regarding how T-box factors regulate gene expression. The Caenorhabditis elegans genome contains 21 T-box genes, and their characterized functions include cell fate specification in a variety of tissues. The C. elegans Tbx1 sub-family member MLS-1 functions during larval development to specify the fate of non-striated uterine muscles; and, in mls-1 mutants, uterine muscles are transformed to a vulval muscle fate. Here we demonstrate that MLS-1 function depends on binding to the Groucho-family co-repressor UNC-37. MLS-1 interacts with UNC-37 via a conserved eh1 motif, and the MLS-1 eh1 motif is necessary for MLS-1 to specify uterine muscle fate. Moreover, unc-37 loss-of-function produces uterine muscle to vulval muscle fate transformation similar to those observed in mls-1 mutants. Based on these results, we conclude that MLS-1 specifies uterine muscle fate by repressing target gene expression, and this function depends on interaction with UNC-37. Moreover, we suggest that MLS-1 shares a common mechanism for transcriptional repression with related T-box factors in other animal phyla.


This project was supported by NIH grant 5R01GM82865. Some nematode strains used in this work were provided by the Caenorhabditis Genetics Center, which is funded by the NIH National Center for Research Resources (NCRR).


Publisher Statement

© 2011 Miller, Okkema. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. DOI: 10.1371/journal.pgen.1002210.


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