Biallelic expression of Tbx1 protects the embryo from developmental defects caused by increased receptor tyrosine kinase signaling

TY - JOUR

T1 - Biallelic expression of Tbx1 protects the embryo from developmental defects caused by increased receptor tyrosine kinase signaling

AU - Simrick, Subreena

AU - Szumska, Dorota

AU - Gardiner, Jennifer R.

AU - Jones, Kieran

AU - Sagar, Karun

AU - Morrow, Bernice

AU - Bhattacharya, Shoumo

AU - Basson, M. Albert

PY - 2012/8

Y1 - 2012/8

N2 - Background: 22q11.2 deletion syndrome (22q11DS) is the most common microdeletion syndrome in humans, characterized by cardiovascular defects such as interrupted aortic arch, outflow tract defects, thymus and parathyroid hypo- or aplasia, and cleft palate. Heterozygosity of Tbx1, the mouse homolog of the candidate TBX1 gene, results in mild defects dependent on genetic background, whereas complete inactivation results in severe malformations in multiple tissues.  Results: The loss of function of two Sprouty genes, which encode feedback antagonists of receptor tyrosine kinase (RTK) signaling, phenocopy many defects associated with 22q11DS in the mouse. The stepwise reduction of Sprouty gene dosage resulted in different phenotypes emerging at specific steps, suggesting that the threshold up to which a given developmental process can tolerate increased RTK signaling is different. Tbx1 heterozygosity significantly exacerbated the severity of all these defects, which correlated with a substantial increase in RTK signaling.  Conclusions: Our findings suggest that TBX1 functions as an essential component of a mechanism that protects the embryo against perturbations in RTK signaling that may lead to developmental defects characteristic of 22q11DS. We propose that genetic factors that enhance RTK signaling ought to be considered as potential genetic modifiers of this syndrome. Developmental Dynamics 241:13101324, 2012. (c) 2012 Wiley Periodicals, Inc.

AB - Background: 22q11.2 deletion syndrome (22q11DS) is the most common microdeletion syndrome in humans, characterized by cardiovascular defects such as interrupted aortic arch, outflow tract defects, thymus and parathyroid hypo- or aplasia, and cleft palate. Heterozygosity of Tbx1, the mouse homolog of the candidate TBX1 gene, results in mild defects dependent on genetic background, whereas complete inactivation results in severe malformations in multiple tissues.  Results: The loss of function of two Sprouty genes, which encode feedback antagonists of receptor tyrosine kinase (RTK) signaling, phenocopy many defects associated with 22q11DS in the mouse. The stepwise reduction of Sprouty gene dosage resulted in different phenotypes emerging at specific steps, suggesting that the threshold up to which a given developmental process can tolerate increased RTK signaling is different. Tbx1 heterozygosity significantly exacerbated the severity of all these defects, which correlated with a substantial increase in RTK signaling.  Conclusions: Our findings suggest that TBX1 functions as an essential component of a mechanism that protects the embryo against perturbations in RTK signaling that may lead to developmental defects characteristic of 22q11DS. We propose that genetic factors that enhance RTK signaling ought to be considered as potential genetic modifiers of this syndrome. Developmental Dynamics 241:13101324, 2012. (c) 2012 Wiley Periodicals, Inc.

U2 - 10.1002/dvdy.23812

DO - 10.1002/dvdy.23812

M3 - Article

SN - 1058-8388

VL - 241

SP - 1310

EP - 1324

JO - Developmental Dynamics

JF - Developmental Dynamics

IS - 8

ER -