Ripply3, a Tbx1 repressor, is required for development of the pharyngeal apparatus and its derivatives in mice.

Okubo T, Kawamura A, Takahashi J, Yagi H, Morishima M, Matsuoka R, Takada S
Development. 2011 138 (2): 339-48

PMID: 21177346 · DOI:10.1242/dev.054056

The pharyngeal apparatus is a transient structure that gives rise to the thymus and the parathyroid glands and also contributes to the development of arteries and the cardiac outflow tract. A typical developmental disorder of the pharyngeal apparatus is the 22q11 deletion syndrome (22q11DS), for which Tbx1 is responsible. Here, we show that Ripply3 can modulate Tbx1 activity and plays a role in the development of the pharyngeal apparatus. Ripply3 expression is observed in the pharyngeal ectoderm and endoderm and overlaps with strong expression of Tbx1 in the caudal pharyngeal endoderm. Ripply3 suppresses transcriptional activation by Tbx1 in luciferase assays in vitro. Ripply3-deficient mice exhibit abnormal development of pharyngeal derivatives, including ectopic formation of the thymus and the parathyroid gland, as well as cardiovascular malformation. Corresponding with these defects, Ripply3-deficient embryos show hypotrophy of the caudal pharyngeal apparatus. Ripply3 represses Tbx1-induced expression of Pax9 in luciferase assays in vitro, and Ripply3-deficient embryos exhibit upregulated Pax9 expression. Together, our results show that Ripply3 plays a role in pharyngeal development, probably by regulating Tbx1 activity.

MeSH Terms (20)

Animals Base Sequence Branchial Region Chromosome Deletion Chromosomes, Human, Pair 22 DNA Primers Female Gene Expression Regulation, Developmental Heart Defects, Congenital Humans Male Mice Mice, 129 Strain Mice, Inbred C57BL Mice, Knockout Paired Box Transcription Factors Phenotype Pregnancy Repressor Proteins T-Box Domain Proteins

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