In the C. elegans germline, GLP-1/Notch signaling and two nearly identical RNA binding proteins, FBF-1 and FBF-2, promote proliferation. Here, we show that the fbf-1 and fbf-2 genes are largely redundant for promoting mitosis but that they have opposite roles in fine-tuning the size of the mitotic region. The mitotic region is smaller than normal in fbf-1 mutants but larger than normal in fbf-2 mutants. Consistent with gene-specific roles, fbf-2 expression is limited to the distal germline, while fbf-1 expression is broader. The fbf-2 gene, but apparently not fbf-1, is controlled by GLP-1/Notch signaling, and the abundance of FBF-1 and FBF-2 proteins is limited by reciprocal 3′UTR repression. We propose that the divergent fbf genes and their regulatory subnetwork enable a precise control over size of the mitotic region. Therefore, fbf-1 and fbf-2 provide a paradigm for how recently duplicated genes can diverge to fine-tune patterning during animal development. Copyright © 2004 by Cell Press.
Lamont, L. B., Crittenden, S. L., Bernstein, D., Wickens, M., & Kimble, J. (2004). FBF-1 and FBF-2 regulate the size of the mitotic region in the C. elegans germline. Developmental Cell, 7(5), 697–707. https://doi.org/10.1016/j.devcel.2004.09.013