title: PEX11β induces peroxisomal gene expression and alters peroxisome number during early Xenopus laevis development.
abstract: BACKGROUND
  Peroxisomes are organelles whose roles in fatty acid metabolism and reactive oxygen species elimination have contributed much attention in understanding their origin and biogenesis. Many studies have shown that de novo peroxisome biogenesis is an important regulatory process, while yeast studies suggest that total peroxisome numbers are in part regulated by proteins such as Pex11, which can facilitate the division of existing peroxisomes. Although de novo biogenesis and divisions are likely important mechanisms, the regulation of peroxisome numbers during embryonic development is poorly understood. Peroxisome number and function are particularly crucial in oviparous animals such as frogs where large embryonic yolk and fatty acid stores must be quickly metabolized, and resulting reactive oxygen species eliminated. Here we elucidate the role of Pex11β in regulating peroxisomal gene expression and number in Xenopus laevis embryogenesis.
  
  
  RESULTS
  Microinjecting haemagglutinin (HA) tagged Pex11β in early embryos resulted in increased RNA levels for peroxisome related genes PMP70 and catalase at developmental stages 10 and 20, versus uninjected embryos. Catalase and PMP70 proteins were found in punctate structures at stage 20 in control embryos, whereas the injection of ectopic HA-Pex11β induced their earlier localization in punctate structures at stage 10. Furthermore, the peroxisomal marker GFP-SKL, which was found localized as peroxisome-like structures at stage 20, was similarly found at stage 10 when co-microinjected with HA-Pex11β.
  
  
  CONCLUSIONS
  Overexpressed Pex11β altered peroxisomal gene levels and induced the early formation of peroxisomes-like structures during development, both of which demonstrate that Pex11β may be a key regulator of peroxisome number in early Xenopus embryos.
authors.affiliation: Department of Biology, University of Western Ontario, 3053 Biological and Geological Sciences Building, 1151 Richmond Street North, London, ON, N6A 5B7, Canada.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Fox
authors.forename: Logan A
authors.initials: LA
authors.lastname: Walsh
authors.forename: Michelle
authors.initials: M
authors.lastname: Nieuwesteeg
authors.forename: Sashko
authors.initials: S
authors.lastname: Damjanovski
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000235:genetics / Q000378:metabolism; D000818:Animals; D002374:Catalase / Q000235:genetics / Q000378:metabolism; D002460:Cell Line; D005227:Fatty Acids / Q000235:genetics / Q000378:metabolism; D005260:Female; D018507:Gene Expression Regulation, Developmental; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D007150:Immunohistochemistry; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D020675:Peroxisomes / Q000235:genetics / Q000378:metabolism*; D012313:RNA / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D029867:Xenopus Proteins / Q000235:genetics* / Q000378:metabolism; D014982:Xenopus laevis / Q000196:embryology* / Q000235:genetics* / Q000378:metabolism
chemical_list: D018528:ATP-Binding Cassette Transporters; D005227:Fatty Acids; D008565:Membrane Proteins; C561582:PEX11B protein, Xenopus; D011994:Recombinant Proteins; D029867:Xenopus Proteins; D049452:Green Fluorescent Proteins; D012313:RNA; D002374:Catalase