Congress Abstracts - Society for Developmental Biology

insights into the ancestral role of Nvlbx1 during endoderm differentiation in Nematostella. In Xenopus, our vertebrate model, we are
using a combination of ChIP-Seq and RNA-Seq to determine potential Lbx1 binding sites and targets. The conserved gene regulatory
network identified in our study should shed light on the evolution of myogenesis in metazoans.
Program/Abstract # 301
The TLR co-receptor TRIL is required for Spemann organizer function in Xenopus
Xie, Yuanyuan (University of Utah, USA); Mimoto, Mizuho; Kwon, Sunjong (Oregon Health & Science University, USA); McKnite,
Autumn; Christian, Jan (University of Utah, USA)
Toll-like receptor (TLR) signaling plays an evolutionarily conserved role in innate immunity. The first identified TLR, Drosophila
Toll, has an essential role in dorsal-ventral patterning, whereas a similar role for vertebrate TLRs has not been uncovered. I have
shown that the novel transmembrane protein, TRIL, which was originally identified as a TLR co-receptor necessary to activate NF-kB
in immune cells, is required for embryonic patterning in Xenopus. Xenopus TRIL is expressed in dorsal mesodermal cells that make up
the Spemann organizer during gastrulation. Targeting TRIL antisense morpholinos to dorsal cells in Xenopus embryos causes
gastrulation defects and spina bifida as well as loss of head and eyes at the tailbud stage. In situ hybridization and immunostaining
analyses suggest that TRIL is required for formation of the notochord and the central nervous system. Gene expression analyses show
that TRIL regulates expression of a subset of organizer genes, including BMP antagonists, during gastrulation. We hypothesize that
TRIL activates a TLR/NF-kB signaling pathway during gastrulation to regulate expression of BMP antagonists and other organizer
genes required for neural induction and dorsal mesoderm formation. These findings suggest that the role of Toll/NF-kB signaling in
regulating expression of BMP antagonists required for dorsal-ventral axis formation is conserved from flies to vertebrates.
Program/Abstract # 302
Fuz mutant mice reveal shared mechanisms between ciliopathies and FGF related syndromes
Tabler, Jacqueline Marie (UT Austin, USA); Liu, Karen (King’s College London, UK); Wallingford, John (UT Austin, USA)
Ciliopathies are a broad class of human disorders, with craniofacial dysmorphology as a common feature. Among the hallmarks of
ciliopathies is high arched palate, a condition that impairs speech and reduces quality of life. We present here the ciliopathic Fuzzy
mutant mouse as the first animal model of high arched palate. Using mouse and frog, we show that this defect arises not, as commonly
suggested, from midface hypoplasia, but rather from increased neural crest expanding the first branchial arch, resulting in maxillary
hyperplasia. High arched palate is also common in fibroblast growth factor (FGF) hyperactivation syndromes, and we find that
craniofacial Fgf8 gene expression is significantly expanded in Fuz mutant mice. Moreover, genetic reduction of Fgf8 levels in Fuz
mutant mice ameliorates the maxillary phenotypes. Finally, the mouse model of oral-facial-digital syndrome-1 (ofd1) also shows
expanded domains of Fgf8 expression accompanied by an enlarged maxillary process, suggesting that aberrant FGF regulation is a
common feature of ciliopathies. Thus, our findings reveal a cause for a common craniofacial anomaly and identify a novel etiological
link between two classes of human disease: FGF-hyperactivation syndromes and ciliopathies.
Program/Abstract # 303
SUMOylated Sox3 is associated with chromatin and affects Sox3 function during zebrafish development
Lam, Chi Man; Laghari, Zulfiqar Ali; Shih, Yu-Huan; Kuo, Cheng-Liang; Struebing, Silke; Scotting, Paul John (University of
Nottingham, UK)
Sox3 is a transcription factor participating in many developmental processes. However, it remains unclear how it is modified and
regulated to function differently at certain times and locations in developing embryos. Our study investigates the role of Sox3
SUMOylation. SUMOylation has been shown previously to have diverse effects on the activity of several transcription factors. Our
previous results suggested that Sox3 directly represses organizer genes in zebrafish. Here we look at how the function of Sox3 on
organizer formation is regulated by SUMOylation. Our cell fractionation and western blot results demonstrated that SUMOylated
Sox3 is associated with chromatin. Luciferase assays also demonstrated that SUMOylation of Sox3 alters its transcriptional activity
and therefore enhances the repressing function of Sox3 on organizer formation in zebrafish. Overall, these results suggest that
SUMOylation of Sox3 is critical to control of its different activities during zebrafish development.
Program/Abstract # 304
Determining the role of an uncharacterized tubulin in the development of multiciliated epithelial cells in Xenopus laevis.
Wills, Airon (University of Texas, Austin, USA), Turk, Erin (Stanford, USA); Sedzinski, Jakub (University of Texas, Austin, USA);
Howes, Stuart; Nogales, Eva (UC Berkeley, USA); Stearns, Tim (Stanford, USA); Wallingford, John (University of Texas, Austin,
USA)
The tubulin superfamily is a well-conserved and ancient protein family. The most well-known members of this superfamily are alpha,
beta, and gamma tubulin, which are found in all eukaryotes and form the structure of the microtubule, and nucleate microtubules,
respectively. However, a number of other tubulin family members have been variably inherited during evolution. Here, we present our
study of a vertebrate tubulin that we have termed “eta-tubulin” due to its similarity with the eta-tubulin protein described in
Paramecium. To our knowledge, eta-tubulin is the only member of the tubulin superfamily that remains completely uncharacterized in
vertebrates. Here, we find that morpholino knockdown of eta-tubulin in Xenopus laevis embryos significantly shortens axoneme
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