Molecular Characterization of the Surfactant, Pulmonary-Associated Protein A1 (SFTPA1) Gene in Horse (Equus caballus)

The Surfactant, Pulmonary-Associated Protein A1 (SFTPA1) gene is one of the key regulators for normal respiration, synthesis, secretion and recycling of surfactant phospholipids. Furthermore, it counteracts the inhibitory effects of plasma proteins released during lung injury on surfactant function. For a better understanding of the SFTPA1 gene in horse (Equus caballus), we retrieved SFTPA1 genomic sequences of horse from the National Center for Biotechnology Information (NCBI) database and performed molecular analyses to obtain insights on this gene and its expression profile in the tissues of horse. Results of the analysis showed that the protein of the SFTPA1 gene in horse was not modified by using the Ka/Ks ratio (ratio of non-synonymous substitutions per site to that of synonymous substitutions per site) and was highly conserved when analyzed and compared with that of other species. Unlike in humans and mice, the SFTPA1 mRNA in horse was detected in the thyroid gland as well as in the lungs of Thoroughbred and Jeju horses. This study was conducted to obtain insights on the genomic characterization and the role of the SFTPA1 gene in horse, information which may be useful in future studies of its association with respiratory system diseases in horses.