Characterization of the porcine FBX07 gene: the first step towards generation of a pig model for Parkinsonian pyramidal syndrome

Abstract

Parkinsonian pyramidal syndrome, also named pallido-pyramidal syndrome (PKPS), is the combination of early-onset progressive Parkinsonism with pyramidal tract signs. FBXO7, an F-box protein, is a component of modular E3 ubiquitin protein ligases called SCFs (SKP1, cullin, F-box proteins), which functions in phosphorylation-dependent ubiquitination. FBXO7 mutations cause autosomal recessive, early-onset PKPS. Here we report the molecular cloning and characterization of two isoforms of FBXO7 cDNA from pigs. The encoded FBXO7 protein displays a very high homology to human FBXO7 with an amino acid identity of 90%. Phylogenetic analysis demonstrated that porcine FBXO7 is closely related to other mammalian FBXO7 proteins. Furthermore, the genomic structure of the porcine FBXO7 gene was determined. The intron-exon structure is similar to that of the human FBXO7 gene. The promoter sequence for the porcine FBXO7 gene was also identified. A recognition site for miR-301a was found in the 3'UTR region of porcine FBXO7. Investigating the genetic variation in the porcine FBXO7 gene revealed a missense A/G SNP in exon 5. The A/G SNP results in a substitution of an asparagine to a serine residue (N269S). Using a radiation hybrid map the FBXO7 gene was mapped to pig chromosome 5. Real-time quantitative RT-PCR analysis revealed that FBXO7 mRNA is differentially expressed in many tissues and organs, and that FBXO7 transcript can be detected early in embryo development.