Abstract
The major apoprotein associated with lung surfactant is a 35 kDa, sialoglycoprotein with an isoelectric point (pl) of 4.5. We used antibodies directed against the major rabbit lung surfactant apoprotein to characterize the induction of this protein during rabbit fetal lung development. Proteins from homo-genates of fetal lung tissue were separated by two-dimensional (2D) gel electrophoresis, transferred to nitrocellulose paper and analyzed using an immunoblot technique. An immunoreactive apoprotein of 26 kDa, pl 4.5, was first detectable on day 24 of gestation. Based on its migration in 2D gels, the protein did not appear to contain sialic acid. The 35 kDa form of the protein was first detectable in lung homogenates from day 30 fetal rabbits. Lamellar bodies (LB), the storage form of surfactant in the type II cell, are first observed on day 26 of gestation. LB were purified from lung tissues of fetuses of 28 and 30 days gestation and their apoproteins were analyzed using immunoblot techniques. The apoprotein associated with the purified LB was the 35 kDa form of the protein. Therefore, a post-translational modification of the 26 kDa protein, possibly the addition of sialic acid residues, may be required for the association of the surfactant apoprotein with LB in the fetal lung type II cell.
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Snyder, J., Mendelson, C. & Rosenfeld, C. 314 INDUCTION OF THE MAJOR SURFACTANT APOPROTEIN DURINC RABBIT FETAL LUNG DEVELOPMENT. Pediatr Res 19, 163 (1985). https://doi.org/10.1203/00006450-198504000-00344
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DOI: https://doi.org/10.1203/00006450-198504000-00344