RESUMEN
Trappins are found in human, bovine, hippopotamus, and members of the pig family, but not in rat and mouse. To clarify the evolution of the trappin genes and the functional significance of their products, we isolated the trappin gene in guinea pig, a species belonging to a rodent family distinct from rat and mouse. Guinea pig trappin was confirmed to encode the same domain structure as trappin, consisting of a signal sequence, an extra large transglutaminase substrate domain, and a whey acidic protein motif. Northern blot analysis and in situ hybridization histochemistry as well as immunohistochemistry demonstrated that guinea pig trappin is expressed solely in the secretory epithelium of the seminal vesicle and that its expression is androgen-dependent. We confirmed that guinea pig trappin is cross-linked by prostate transglutaminase and that the whey acidic protein motif derived from guinea pig trappin has an inhibitory activity against leukocyte elastase. Genome sequence analysis showed that guinea pig trappin belongs to the family of REST (rapidly evolving seminal vesicle transcribed) genes.
Asunto(s)
Evolución Molecular , Regulación de la Expresión Génica , Proteínas/análisis , Proteínas/genética , Transglutaminasas/metabolismo , Secuencia de Aminoácidos , Andrógenos/farmacología , Animales , Sitios de Unión , Western Blotting , Calcio/farmacología , Bovinos , Reactivos de Enlaces Cruzados , ADN Complementario/química , Regulación de la Expresión Génica/efectos de los fármacos , Cobayas , Humanos , Inmunohistoquímica , Elastasa de Leucocito/antagonistas & inhibidores , Masculino , Ratones , Proteínas de la Leche/química , Proteínas de la Leche/metabolismo , Datos de Secuencia Molecular , Próstata/enzimología , Proteínas Inhibidoras de Proteinasas Secretoras , Proteínas/química , Ratas , Vesículas Seminales/química , Alineación de Secuencia , Porcinos , Distribución TisularRESUMEN
We determined the cDNA and gene structures of guinea pig caltrin II, a unique member of the calcium transporter inhibitors containing a whey acidic protein (WAP) motif, and we established that it is a secretory protein with a potential 21-amino acid signal peptide in its N-terminus. Northern blot analysis and in situ hybridization histochemistry indicated that the expression of caltrin II is restricted to luminal epithelial cells in the seminal vesicles. Its message levels markedly decreased either after castration (and were restored by simultaneous administration of testosterone) or after treatment of the animals with estradiol, suggesting that the expression of caltrin II is androgen-dependent. Recombinant caltrin II had an elastase-inhibitor activity. Comparison of sequence between the caltrin II and related genes and their molecular evolutionary analyses revealed that caltrin II and seminal vesicle secretory proteins (SVPs) appear to be evolved from a common ancestor gene that is made by the fusion of semenogelin and trappin genes. Caltrin II and SVPs lost the transglutaminase substrate domain and the WAP motif, respectively, within a single exon, resulting in the exertion of different functions.