The essential role of Cited2, a negative regulator for HIF-1alpha, in heart development and neurulation.
Cited2 is a cAMP-responsive element-binding protein (CBP)/p300 interacting transcriptional modulator and a proposed negative regulator for hypoxia-inducible factor (HIF)-1alpha through its competitive binding with HIF-1alpha to CBP/p300. Disruption of the gene encoding Cited2 is embryonic lethal because of defects in the development of heart and neural tube. Morphological and Doppler echocardiographic analyses of Cited2(-/-) embryos reveal severe cardiovascular abnormalities, including pulmonic arterial stenosis and ventricular septal defects accompanied by high peak outflow velocities, features of the human congenital cardiac defect termed tetralogy of Fallot. The mRNA levels of several HIF-1alpha-responsive genes, such as vascular endothelial growth factor (VEGF), Glut1, and phosphoglycerate kinase 1, increased in the Cited2(-/-) hearts. The increase of VEGF levels is significant, because defects in the Cited2(-/-) embryos closely resemble the major defects observed in the VEGF transgenic embryos. Finally, compared with wild-type, cultured fibroblasts from Cited2(-/-) embryos demonstrate an enhanced expression of HIF-1alpha-responsive genes under hypoxic conditions. These observations suggest that functional loss of Cited2 is responsible for defects in heart and neural tube development, in part because of the modulation of HIF-1 transcriptional activities in the absence of Cited2. These findings demonstrate that Cited2 is an indispensable regulatory gene during prenatal development.
Yin
Zhan
Z
Department of Pharmacology and Cancer Center, University Hospitals of Cleveland, OH 44106-4965, USA.
Haynie
Jennifer
J
Yang
Xiaoming
X
Han
Baoguang
B
Kiatchoosakun
Songsak
S
Restivo
Joseph
J
Yuan
Saying
S
Prabhakar
Nanduri R
NR
Herrup
Karl
K
Conlon
Ronald A
RA
Hoit
Brian D
BD
Watanabe
Michiko
M
Yang
Yu-Chung
YC
D000818:Animals; D002478:Cells, Cultured; D004268:DNA-Binding Proteins; D015150:Echocardiography, Doppler / Q000379:methods; D005260:Female; D005347:Fibroblasts / Q000166:cytology; D018507:Gene Expression Regulation, Developmental; D006321:Heart / Q000196:embryology*; D006330:Heart Defects, Congenital / Q000209:etiology; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009436:Neural Tube Defects / Q000209:etiology; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D014157:Transcription Factors / Q000378:metabolism*
C486381:CITED2 protein, human; C110087:Cited2 protein, mouse; D004268:DNA-Binding Proteins; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D012097:Repressor Proteins; D015534:Trans-Activators; D014157:Transcription Factors