A novel model of autosomal recessive polycystic kidney questions the role of the fibrocystin C-terminus in disease mechanism.
Kidney Int
; 92(5): 1130-1144, 2017 11.
Article
en En
| MEDLINE
| ID: mdl-28729032
ABSTRACT
Autosomal recessive polycystic kidney disease (OMIM 263200) is a serious condition of the kidney and liver caused by mutations in a single gene, PKHD1. This gene encodes fibrocystin/polyductin (FPC, PD1), a large protein shown by in vitro studies to undergo Notch-like processing. Its cytoplasmic tail, reported to include a ciliary targeting sequence, a nuclear localization signal, and a polycystin-2 binding domain, is thought to traffic to the nucleus after cleavage. We now report a novel mouse line with a triple HA-epitope "knocked-in" to the C-terminus along with lox P sites flanking exon 67, which encodes most of the C-terminus (Pkhd1Flox67HA). The triple HA-epitope has no functional effect as assayed by phenotype and allows in vivo tracking of Fibrocystin. We used the HA tag to identify previously predicted Fibrocystin cleavage products in tissue. In addition, we found that Polycystin-2 fails to co-precipitate with Fibrocystin in kidney samples. Immunofluorescence studies with anti-HA antibodies demonstrate that Fibrocystin is primarily present in a sub-apical location the in kidney, biliary duct, and pancreatic ducts, partially overlapping with the Golgi. In contrast to previous studies, the endogenous protein in the primary cilia was not detectable in mouse tissues. After Cre-mediated deletion, homozygous Pkhd1Δ67 mice are completely normal. Thus, Pkhd1Flox67HA is a valid model to track Pkhd1-derived products containing the C-terminus. Significantly, exon 67 containing the nuclear localization signal and the polycystin-2 binding domain is not essential for Fibrocystin function in our model.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Riñón Poliquístico Autosómico Recesivo
/
Receptores de Superficie Celular
/
Canales Catiónicos TRPP
/
Dominios Proteicos
/
Riñón
Tipo de estudio:
Prognostic_studies
Límite:
Animals
/
Female
/
Humans
/
Male
Idioma:
En
Revista:
Kidney Int
Año:
2017
Tipo del documento:
Article
País de afiliación:
Estados Unidos