FBXO7 sensitivity of phenotypic traits elucidated by a hypomorphic allele

PLoS One. 2019 Mar 6;14(3):e0212481. doi: 10.1371/journal.pone.0212481. eCollection 2019.

Abstract

FBXO7 encodes an F box containing protein that interacts with multiple partners to facilitate numerous cellular processes and has a canonical role as part of an SCF E3 ubiquitin ligase complex. Mutation of FBXO7 is responsible for an early onset Parkinsonian pyramidal syndrome and genome-wide association studies have linked variants in FBXO7 to erythroid traits. A putative orthologue in Drosophila, nutcracker, has been shown to regulate the proteasome, and deficiency of nutcracker results in male infertility. Therefore, we reasoned that modulating Fbxo7 levels in a murine model could provide insights into the role of this protein in mammals. We used a targeted gene trap model which retained 4-16% residual gene expression and assessed the sensitivity of phenotypic traits to gene dosage. Fbxo7 hypomorphs showed regenerative anaemia associated with a shorter erythrocyte half-life, and male mice were infertile. Alterations to T cell phenotypes were also observed, which intriguingly were both T cell intrinsic and extrinsic. Hypomorphic mice were also sensitive to infection with Salmonella, succumbing to a normally sublethal challenge. Despite these phenotypes, Fbxo7 hypomorphs were produced at a normal Mendelian ratio with a normal lifespan and no evidence of neurological symptoms. These data suggest that erythrocyte survival, T cell development and spermatogenesis are particularly sensitive to Fbxo7 gene dosage.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alleles*
  • Animals
  • F-Box Proteins* / biosynthesis
  • F-Box Proteins* / genetics
  • Gene Dosage*
  • Gene Expression Regulation*
  • Infertility, Male* / genetics
  • Infertility, Male* / metabolism
  • Male
  • Mice
  • Mice, Transgenic
  • Quantitative Trait, Heritable*
  • Salmonella
  • Salmonella Infections / genetics
  • Spermatogenesis / genetics

Substances

  • F-Box Proteins
  • FBXO7 protein, mouse