Related Experiment Videos
Human PEX1 is mutated in complementation group 1 of the peroxisome biogenesis disorders
H Portsteffen1, A Beyer, E Becker
1Abteilung für Zellbiochemie, Ruhr-Universität Bochum, Germany.
Insights
Researchers identified the human PEX1 gene, crucial for peroxisome biogenesis. Mutations in this gene cause peroxisome biogenesis disorders (PBDs), a group of severe genetic diseases affecting newborns.
Area of Science:
- Genetics
- Molecular Biology
- Biochemistry
Background:
- Peroxisome biogenesis disorders (PBDs) are lethal, genetically diverse diseases.
- PBDs result from mutations in PEX genes, which encode essential peroxins for peroxisome formation.
- Clinical phenotypes range from Zellweger syndrome (most severe) to infantile Refsum's disease (least severe).
Purpose of the Study:
- To identify and characterize the human PEX1 gene, a key player in peroxisome biogenesis.
- To investigate the role of human PEX1 in the context of PBDs.
Main Methods:
- Computer-based homology probing using yeast PEX1 sequence (ScPex1p) to screen human expressed sequence tag databases (dbEST).
- Cloning of the human PEX1 gene.
- Functional complementation assays using PEX1 expression in patient-derived fibroblasts.
Main Results:
- The human PEX1 gene was cloned, encoding a 147-kD AAA protein family member.
- Human PEX1 was identified as the putative orthologue of Saccharomyces cerevisiae Pex1p.
- Expression of PEX1 corrected the peroxisome biogenesis defect in fibroblasts from complementation group 1 (CG1) patients.
- Mutations in PEX1 were confirmed in CG1 patients.
Conclusions:
- The human PEX1 gene is essential for peroxisome biogenesis.
- PEX1 mutations are a cause of peroxisome biogenesis disorders, specifically in complementation group 1.
- This finding provides a molecular basis for understanding and potentially diagnosing certain PBDs.
Abstract:
Human peroxisome biogenesis disorders (PBDs) are a group of genetically heterogeneous autosomal-recessive disease caused by mutations in PEX genes that encode peroxins, proteins required for peroxisome biogenesis. These lethal diseases include Zellweger syndrome (ZS), neonatal adrenoleukodystrophy (NALD) and infantile Refsum's disease (IRD), three phenotypes now thought to represent a continuum of clinical features that are most severe in ZS, milder in NALD and least severe in IRD2. At least eleven PBD complementation groups have been identified by somatic-cell hybridization analysis compared to the eighteen PEX complementation groups that have been found in yeast. We have cloned the human PEX1 gene encoding a 147-kD member of the AAA protein family (ATPases associated with diverse cellular activities), which is the putative orthologue of Saccharomyces cerevisiae Pex1p (ScPex1p). Human PEX1 has been identified by computer-based 'homology probing' using the ScPex1p sequence to screen databases of expressed sequence tags (dbEST) for human cDNA clones. Expression of PEX1 rescued the cells from the biogenesis defect in human fibroblasts of complementation group 1 (CG1), the largest PBD complementation group. We show that PEX1 is mutated in CG1 patients.