Influence of elastin gene polymorphism on the elastin content of the aorta: A study in 2 strains of rat

Abstract

The elastin content in the thoracic aorta of male Brown-Norway (BN) rats is 31.4±1.2% (dry weight), whereas that of male LOU rats is 37.2±1.0%. A similar difference in the elastin content of the thoracic aorta is also observed in female animals. Furthermore, in the thoracic aorta of young, growing rats as well as in cultured aortic smooth muscle cells, the steady- state level of elastin mRNA is significantly lower in the BN than in the LOU strain. These results suggested that I or more genes control the elastin mRNA level and the elastin content in the aortas of BN and LOU rats. A possible relationship between a polymorphism in the elastin gene and the elastin content of the aorta was tested. For this purpose, the aortic elastin content was measured in F1 and F2 generations bred from LOU and BN rats and was compared with that of the F0 (parental) generation. A polymorphic marker located in intron 25 of the elastin gene has been used to genotype the F2 rats. The degree of genetic determination of aortic elastin content was estimated to be 73% in the F2 cohort, but the elastin locus accounts for only 3.9% of the total variance in aortic elastin content. Other genes are thus responsible for the major part of the observed interstrain difference by regulating the transcription of the gene, the stability of elastin mRNA, and/or posttranslational events.