RESUMEN
The iron-sensing protein FBXL5 is the substrate adaptor for a SKP1-CUL1-RBX1 E3 ubiquitin ligase complex that regulates the degradation of iron regulatory proteins (IRPs). Here, we describe a mechanism of FBXL5 regulation involving its interaction with the cytosolic Fe-S cluster assembly (CIA) targeting complex composed of MMS19, FAM96B, and CIAO1. We demonstrate that the CIA-targeting complex promotes the ability of FBXL5 to degrade IRPs. In addition, the FBXL5-CIA-targeting complex interaction is regulated by oxygen (O2) tension displaying a robust association in 21% O2 that is severely diminished in 1% O2 and contributes to O2-dependent regulation of IRP degradation. Together, these data identify a novel oxygen-dependent signaling axis that links IRP-dependent iron homeostasis with the Fe-S cluster assembly machinery.
Asunto(s)
Proteínas de Ciclo Celular/genética , Proteínas F-Box/genética , Chaperonas Moleculares/genética , Complejos Multiproteicos/genética , Complejos de Ubiquitina-Proteína Ligasa/genética , Proteínas de Ciclo Celular/química , Proteínas F-Box/química , Células HeLa , Homeostasis , Humanos , Hierro/metabolismo , Proteínas Reguladoras del Hierro/genética , Proteínas Hierro-Azufre/química , Proteínas Hierro-Azufre/genética , Chaperonas Moleculares/química , Complejos Multiproteicos/química , Oxígeno/metabolismo , Proteolisis , Factores de Transcripción/genética , Complejos de Ubiquitina-Proteína Ligasa/químicaRESUMEN
Gene-drive systems developed in several organisms result in super-Mendelian inheritance of transgenic insertions. Here, we generalize this "active genetic" approach to preferentially transmit allelic variants (allelic-drive) resulting from only a single or a few nucleotide alterations. We test two configurations for allelic-drive: one, copy-cutting, in which a non-preferred allele is selectively targeted for Cas9/guide RNA (gRNA) cleavage, and a more general approach, copy-grafting, that permits selective inheritance of a desired allele located in close proximity to the gRNA cut site. We also characterize a phenomenon we refer to as lethal-mosaicism that dominantly eliminates NHEJ-induced mutations and favors inheritance of functional cleavage-resistant alleles. These two efficient allelic-drive methods, enhanced by lethal mosaicism and a trans-generational drive process we refer to as "shadow-drive", have broad practical applications in improving health and agriculture and greatly extend the active genetics toolbox.