Targeted deletion of the 9p21 non-coding coronary artery disease risk interval in mice.
Sequence polymorphisms in a 58-kilobase (kb) interval on chromosome 9p21 confer a markedly increased risk of coronary artery disease (CAD), the leading cause of death worldwide. The variants have a substantial effect on the epidemiology of CAD and other life-threatening vascular conditions because nearly one-quarter of Caucasians are homozygous for risk alleles. However, the risk interval is devoid of protein-coding genes and the mechanism linking the region to CAD risk has remained enigmatic. Here we show that deletion of the orthologous 70-kb non-coding interval on mouse chromosome 4 affects cardiac expression of neighbouring genes, as well as proliferation properties of vascular cells. Chr4(Delta70kb/Delta70kb) mice are viable, but show increased mortality both during development and as adults. Cardiac expression of two genes near the non-coding interval, Cdkn2a and Cdkn2b, is severely reduced in chr4(Delta70kb/Delta70kb) mice, indicating that distant-acting gene regulatory functions are located in the non-coding CAD risk interval. Allele-specific expression of Cdkn2b transcripts in heterozygous mice showed that the deletion affects expression through a cis-acting mechanism. Primary cultures of chr4(Delta70kb/Delta70kb) aortic smooth muscle cells exhibited excessive proliferation and diminished senescence, a cellular phenotype consistent with accelerated CAD pathogenesis. Taken together, our results provide direct evidence that the CAD risk interval has a pivotal role in regulation of cardiac Cdkn2a/b expression, and suggest that this region affects CAD progression by altering the dynamics of vascular cell proliferation.
Visel
Axel
A
Genomics Division, MS 84-171, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
Zhu
Yiwen
Y
May
Dalit
D
Afzal
Veena
V
Gong
Elaine
E
Attanasio
Catia
C
Blow
Matthew J
MJ
Cohen
Jonathan C
JC
Rubin
Edward M
EM
Pennacchio
Len A
LA
D000818:Animals; D001011:Aorta / Q000473:pathology; D049109:Cell Proliferation; D002478:Cells, Cultured; D016922:Cellular Senescence / Q000235:genetics; D002872:Chromosome Deletion; D002899:Chromosomes, Human, Pair 9 / Q000235:genetics; D033481:Chromosomes, Mammalian / Q000235:genetics*; D003324:Coronary Artery Disease / Q000235:genetics* / Q000473:pathology; D050762:Cyclin-Dependent Kinase Inhibitor p15 / Q000172:deficiency / Q000235:genetics; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000172:deficiency / Q000235:genetics; D004622:Embryo, Mammalian / Q000196:embryology; D005786:Gene Expression Regulation / Q000235:genetics; D020022:Genetic Predisposition to Disease / Q000235:genetics; D006801:Humans; D051379:Mice; D032389:Myocytes, Smooth Muscle / Q000473:pathology; D016019:Survival Analysis
C417743:Cdkn2a protein, mouse; C493968:Cdkn2b protein, mouse; D050762:Cyclin-Dependent Kinase Inhibitor p15; D019941:Cyclin-Dependent Kinase Inhibitor p16