RESUMEN

Terminal deoxynucleotidyltransferase (TdT), which template-independently synthesizes DNA during V(D)J recombination in lymphoid cells, is ubiquitylated by a BPOZ-2/Cul3 complex, as the ubiquitin ligase, and then degraded by the 26 S proteasome. We show here that TdT is ubiquitylated by the Cul3-based ubiquitylation system in vitro. Because TdT could also be ubiquitylated in the absence of Cul/BPOZ-2, we determined that it could also be directly ubiquitylated by the E2 proteins UbcH5a/b/c and UbcH6, E3-independently. Furthermore, the ubiquitylated TdT inhibited its nucleotidyltransferase activity.

Asunto(s)

ADN Nucleotidilexotransferasa/metabolismo , Retroalimentación Fisiológica , Regulación de la Expresión Génica , Ubiquitinación/genética , Animales , Bovinos , Proteínas Cullin/genética , Proteínas Cullin/metabolismo , ADN Nucleotidilexotransferasa/genética , Biblioteca de Genes , Células HeLa , Humanos , Hígado/citología , Hígado/metabolismo , Plásmidos , Complejo de la Endopetidasa Proteasomal/genética , Complejo de la Endopetidasa Proteasomal/metabolismo , Proteolisis , Proteínas Represoras/genética , Proteínas Represoras/metabolismo , Timo/citología , Timo/metabolismo , Transfección , Enzimas Ubiquitina-Conjugadoras/genética , Enzimas Ubiquitina-Conjugadoras/metabolismo , Ubiquitina-Proteína Ligasas/genética , Ubiquitina-Proteína Ligasas/metabolismo