Genetic and molecular analysis in the 70CD region of the third chromosome of Drosophila melanogaster
GENE
Authors: Burmester, T; Mink, M; Pal, M; Laszloffy, Z; Lepesant, JA; Maroy, P
Abstract
A collection of lethal and semi-lethal P-element insertions in the 70CD region of chromosome 3 of Drosophila melanogaster was used to investigate genes and gene arrangements by a combination of genetic, cytological, functional and molecular methods. The 12 lethal insertions studied fall into seven complementation groups of six genes. Lethal phases, expression patterns and other phenotypic aspects of these genes were determined. The genes and additional available sequences were placed on cloned genomic DNA fragments and arranged in an EcoRI map of 150 kb that covers approximately the bands 70C7-8 to 70D1. Determination of deficiency breakpoints links the genetic, physical and molecular data. The sequences adjacent to seven independent P-element insertions were established after plasmid rescue or polymerase chain reaction. Similarity searches allowed the assignment of the P-element insertions to known mutations, expressed sequence tags, sequence tagged sites, or homologous genes of other species. Among these were identified a putative transacylase, a putative cell cycle gene, and the gene responsible for the dominant Polycomb-suppressor phenotype of devenii. The genomic sequence of the l(3)70Ca/b gene reveals a novel heat shock protein (hsc70Cb). l(3) 70Da was identified as a member of the CDC48/PEX1 ATPase family and its coding sequence was determined. (C) 2000 Elsevier Science B.V. All rights reserved.
The Pex1-G844D mouse: A model for mild human Zellweger spectrum disorder
MOLECULAR GENETICS AND METABOLISM
Authors: Hiebler, Shandi; Masuda, Tomohiro; Hacia, Joseph G.; Moser, Ann B.; Faust, Phyllis L.; Liu, Anita; Chowdhury, Nivedita; Huang, Ning; Lauer, Amanda; Bennett, Jean; Watkins, Paul A.; Zack, Donald J.; Braverman, Nancy E.; Raymond, Gerald V.; Steinberg, Steven J.
Abstract
Zellweger spectrum disorder (ZSD) is a disease continuum that results from inherited defects in PEX genes essential for normal peroxisome assembly. These autosomal recessive disorders impact brain development and also cause postnatal liver, adrenal, and kidney dysfunction, as well as loss of vision and hearing. The hypomorphic PEX1-G843D missense allele, observed in approximately 30% of ZSD patients, is associated with milder clinical and biochemical phenotypes, with some homozygous individuals surviving into early adulthood. Nonetheless, affected children with the PEX1-G843D allele have intellectual disability, failure to thrive, and significant sensory deficits. To enhance our ability to test candidate therapies that improve human PEX1-G843D function, we created the novel Pex1-G844D knock-in mouse model that represents the murine equivalent of the common human mutation. We show that Pex1-G844D homozygous mice recapitulate many classic features of mild ZSD cases, including growth retardation and fatty livers with cholestasis. In addition, electrophysiology, histology, and gene expression studies provide evidence that these animals develop a retinopathy similar to that observed in human patients, with evidence of cone photoreceptor cell death. Similar to skin fibroblasts obtained from ZSD patients with a PEX1-G843D allele, we demonstrate that murine cells homozygous for the Pex1-G844D allele respond to chaperone-like compounds, which normalizes peroxisomal beta-oxidation. Thus, the Pex1-G844D mouse provides a powerful model system for testing candidate therapies that address the most common genetic cause of ZSD. In addition, this murine model will enhance studies focused on mechanisms of pathogenesis. (C) 2014 Elsevier Inc. All rights reserved.