Identification of novel OCRL isoforms associated with phenotypic differences between Dent disease-2 and Lowe syndrome.
Nephrol Dial Transplant
; 37(2): 262-270, 2022 01 25.
Article
em En
| MEDLINE
| ID: mdl-34586410
ABSTRACT
BACKGROUND:
Although Lowe syndrome and Dent disease-2 are caused by Oculocerebrorenal syndrome of Lowe (OCRL) mutations, their clinical severities differ substantially and their molecular mechanisms remain unclear. Truncating mutations in OCRL exons 1-7 lead to Dent disease-2, whereas those in exons 8-24 lead to Lowe syndrome. Herein we identified the mechanism underlying the action of novel OCRL protein isoforms.METHODS:
Messenger RNA samples extracted from cultured urine-derived cells from a healthy control and a Dent disease-2 patient were examined to detect the 5' end of the OCRL isoform. For protein expression and functional analysis, vectors containing the full-length OCRL transcripts, the isoform transcripts and transcripts with truncating mutations detected in Lowe syndrome and Dent disease-2 patients were transfected into HeLa cells.RESULTS:
We successfully cloned the novel isoform transcripts from OCRL exons 6-24, including the translation-initiation codons present in exon 8. In vitro protein-expression analysis detected proteins of two different sizes (105 and 80 kDa) translated from full-length OCRL, whereas only one protein (80 kDa) was found from the isoform and Dent disease-2 variants. No protein expression was observed for the Lowe syndrome variants. The isoform enzyme activity was equivalent to that of full-length OCRL; the Dent disease-2 variants retained >50% enzyme activity, whereas the Lowe syndrome variants retained <20% activity.CONCLUSIONS:
We elucidated the molecular mechanism underlying the two different phenotypes in OCRL-related diseases; the functional OCRL isoform translated starting at exon 8 was associated with this mechanism.Palavras-chave
Texto completo:
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Base de dados:
MEDLINE
Assunto principal:
Monoéster Fosfórico Hidrolases
/
Doença de Dent
/
Síndrome Oculocerebrorrenal
Tipo de estudo:
Diagnostic_studies
/
Prognostic_studies
/
Risk_factors_studies
Limite:
Humans
Idioma:
En
Ano de publicação:
2022
Tipo de documento:
Article