Essential functions of the Williams-Beuren syndrome-associated TFII-I genes in embryonic development.

Abstract

GTF2I and GTF2IRD1 encoding the multifunctional transcription factors TFII-I and BEN are clustered at the 7q11.23 region hemizygously deleted in Williams-Beuren syndrome (WBS), a complex multisystemic neurodevelopmental disorder. Although the biochemical properties of TFII-I family transcription factors have been studied in depth, little is known about the specialized contributions of these factors in pathways required for proper embryonic development. Here, we show that homozygous loss of either Gtf2ird1 or Gtf2i function results in multiple phenotypic manifestations, including embryonic lethality; brain hemorrhage; and vasculogenic, craniofacial, and neural tube defects in mice. Further analyses suggest that embryonic lethality may be attributable to defects in yolk sac vasculogenesis and angiogenesis. Microarray data indicate that the Gtf2ird1 homozygous phenotype is mainly caused by an impairment of the genes involved in the TGFbetaRII/Alk1/Smad5 signal transduction pathway. The effect of Gtf2i inactivation on this pathway is less prominent, but downregulation of the endothelial growth factor receptor-2 gene, resulting in the deterioration of vascular signaling, most likely exacerbates the severity of the Gtf2i mutant phenotype. A subset of Gtf2ird1 and Gtf2i heterozygotes displayed microcephaly, retarded growth, and skeletal and craniofacial defects, therefore showing that haploinsufficiency of TFII-I proteins causes various developmental anomalies that are often associated with WBS.

• Authors: Badam Enkhmandakh, Aleksandr V Makeyev, Lkhamsuren Erdenechimeg, Frank H Ruddle, Nyam-Osor Chimge, Maria Isabel Tussie-Luna, Ananda L Roy, Dashzeveg Bayarsaihan
• Journal: Proceedings of the National Academy of Sciences of the United States of America (Proc Natl Acad Sci U S A) Vol. 106 Issue 1 Pg. 181-6 (Jan 06 2009) ISSN: 1091-6490 [Electronic] United States
• PMID: 19109438 (Publication Type: Journal Article, Research Support, N.I.H., Extramural)

Chemical References

• Gtf2i protein, mouse
• Transcription Factors, TFII
• Transforming Growth Factor beta

Topics

• Abnormalities, Multiple (genetics)
• Animals
• Embryonic Development (genetics)
• Gene Expression Profiling
• Heterozygote
• Mice
• Phenotype
• Signal Transduction (genetics)
• Transcription Factors, TFII (genetics)
• Transforming Growth Factor beta
• Williams Syndrome (genetics)