Characterization of a gene encoding a novel peroxisomal matrix protein, PXEL
- Johns Hopkins Univ. School of Medicine, Baltimore, MD (United States)
Disorders of peroxisomal biogenesis and function are associated with a variety of severe autosomal and X-linked recessive clinical phenotypes. To identify the genes involved in these functions we have used the Wang & Brown subtractive hybridization method to isolated rat liver cDNAs upregulated by treatment with clofibrate and di(ethylhexyl)pthalate. These substances are known to induce peroxisome proliferation in rodent hepatocytes. In a pilot study of the 53 upregulated gene fragments isolated and sequenced using this method, 20 (37.7%) were known peroxisomal genes. Two of the remaining clones were fragments of a previously unknown cDNA that showed >20-fold induction. The full-length cDNA was isolated and has a single open reading frame that predicts a protein product of 36 kDa with a C-terminal peroxisomal targeting signal (-SKL). This protein was epitope-tagged with a C-myc dodecapeptide and found to be efficiently imported into peroxisomes in HEK293 cells by double-label immuno-fluorescence. A search of the protein sequence against the public databases revealed homology to enoyl-CoA hydratases from a wide variety of species. We have named this gene peroxisomal enoyl-CoA hydratase-like (PXEL). We have also isolated orthologous cDNAs from a human retinal cDNA library that show >85% identity in both nucleotide and amino acid sequence when compared to rat PXEL. Using hybridization to somatic cell hybrid DNA and chromosome 19-specific cosmid arrays, we were able to physically map the human PXEL gene to 19q13.1 in a contig 3{prime} to the ryanodine receptor. Northern blot analysis of tissue distribution showed high levels of expression of a 1.4 kb message in skeletal and heart muscle with a detectable transcript in every tissue examined. To investigate the function of this gene we are in the process of examining patients with disorders of peroxisomal {beta}-oxidation for mutations in the PXEL gene.
- OSTI ID:
- 133306
- Report Number(s):
- CONF-941009-; ISSN 0002-9297; TRN: 95:005313-0033
- Journal Information:
- American Journal of Human Genetics, Vol. 55, Issue Suppl.3; Conference: 44. annual meeting of the American Society of Human Genetics, Montreal (Canada), 18-22 Oct 1994; Other Information: PBD: Sep 1994
- Country of Publication:
- United States
- Language:
- English
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