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

Development. 2011 Jan;138(2):339-48. 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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Base Sequence
  • Branchial Region / abnormalities
  • Branchial Region / embryology*
  • Branchial Region / metabolism*
  • Chromosome Deletion
  • Chromosomes, Human, Pair 22 / genetics
  • DNA Primers / genetics
  • Female
  • Gene Expression Regulation, Developmental
  • Heart Defects, Congenital / embryology
  • Heart Defects, Congenital / genetics
  • Humans
  • Male
  • Mice
  • Mice, 129 Strain
  • Mice, Inbred C57BL
  • Mice, Knockout
  • PAX9 Transcription Factor
  • Paired Box Transcription Factors / genetics
  • Phenotype
  • Pregnancy
  • Repressor Proteins / deficiency
  • Repressor Proteins / genetics
  • Repressor Proteins / physiology*
  • T-Box Domain Proteins / antagonists & inhibitors
  • T-Box Domain Proteins / genetics
  • T-Box Domain Proteins / metabolism*


  • DNA Primers
  • PAX9 Transcription Factor
  • Paired Box Transcription Factors
  • Pax9 protein, mouse
  • Repressor Proteins
  • T-Box Domain Proteins
  • TBX1 protein, human
  • Tbx1 protein, mouse