Elastin mRNA levels and insoluble elastin accumulation in neonatal rat smooth muscle cell cultures

Insoluble elastin accumulation, elastin mRNA translational efficiencies, and elastin mRNA levels were evaluated in cultures of neonatal rat aortic smooth muscle cells grown for several days in consecutive passages. When the products of in vitro translation were immunoprecipitated with an anti-alpha-elastin antibody, a single 79,000-Da protein was obtained. Northern blot analysis also indicated an elastin mRNA species corresponding to approximately 4.2 kilobases. Insoluble elastin accumulation increased in cells cultured for 7-21 days in first through fourth passages, while with one exception, relative levels and translational activity of elastin mRNA decreased with time in culture. The data indicated that a simple relationship between elastin accumulation and elastin mRNA levels was not evident.