RESUMEN

Polyamines are low molecular weight aliphatic compounds involved in various biochemical, cellular and physiological processes in all organisms. In plants, genes involved in polyamine biosynthesis and catabolism are regulated at transcriptional, translational, and posttranslational level. In this research, we focused on the characterization of a PEST sequence (rich in proline, glutamic acid, serine, and threonine) of the maize spermine synthase 1 (ZmSPMS1). To this aim, 123 bp encoding 40 amino acids of the C-terminal region of the ZmSPMS1 enzyme containing the PEST sequence were fused to the GUS reporter gene. This fusion was evaluated in Arabidopsis thaliana transgenic lines and onion monolayers transient expression system. The ZmSPMS1 PEST sequence leads to specific degradation of the GUS reporter protein. It is suggested that the 26S proteasome may be involved in GUS::PEST fusion degradation in both onion and Arabidopsis. The PEST sequences appear to be present in plant spermine synthases, mainly in monocots.

Asunto(s)

Glucuronidasa/metabolismo , Proteínas de Plantas/metabolismo , Proteolisis , Espermina Sintasa/metabolismo , Zea mays/metabolismo , Secuencia de Aminoácidos , Arabidopsis/genética , Arabidopsis/metabolismo , Western Blotting , Inhibidores de Cisteína Proteinasa/farmacología , Genes de Plantas/genética , Glucuronidasa/genética , Leupeptinas/farmacología , Datos de Secuencia Molecular , Cebollas/citología , Cebollas/genética , Cebollas/metabolismo , Proteínas de Plantas/genética , Plantas Modificadas Genéticamente , Complejo de la Endopetidasa Proteasomal/metabolismo , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Espermina Sintasa/genética , Zea mays/genética