title: An Antibody to Detect Alanine-Expanded PABPN1: A New Tool to Study Oculopharyngeal Muscular Dystrophy.
abstract: BACKGROUND
  Oculopharyngeal muscular dystrophy (OPMD), a late onset disorder affecting specific skeletal muscles, is caused by a (GCG)n expansion mutation in the gene encoding the mRNA processing protein, polyadenylate binding protein nuclear 1 (PABPN1). The expansion in PABPN1 leads to an increase in a stretch of N-terminal alanine residues in the PABPN1 protein from the normal 10 to 12-18. Given this modest change, detection of mutant protein has not been possible without the use of tagged constructs.
  
  
  OBJECTIVE
  We sought to generate a polyclonal antibody that recognizes alanine-expanded but not wild type PABPN1 with the goal of making possible analysis of expression and localization of alanine-expanded PABPN1.
  
  
  METHODS
  We immunized rabbits with a GST-tagged alanine peptide and tested the resulting serum against alanine-expanded PABPN1 expressed in cell culture as well as in animal models of OPMD.
  
  
  RESULTS
  The resulting α-alanine antibody detected PABPN1 proteins that contained 14 or more alanine residues. Importantly, the α-alanine antibody could be used to detect alanine-expanded PABPN1 in muscles from either a mouse or Drosophila model of OPMD.
  
  
  CONCLUSIONS
  This α-alanine antibody provides a new tool that will allow for more in-depth study of how alanine expansion affects aggregation, localization, and steady-state levels of alanine-expanded PABPN1 levels in vivo, providing new insight into the molecular mechanisms underlying OPMD.
authors.affiliation: Department of Biochemistry, Emory University School of Medicine, Atlanta, GA, USA.|Department of Pharmacology, Emory University School of Medicine, Atlanta, GA, USA.
authors.forename: Katherine E
authors.initials: KE
authors.lastname: Vest
authors.affiliation: Department of Pharmacology, Emory University School of Medicine, Atlanta, GA, USA.|Dicerna Pharmaceuticals, Inc., Cambridge, MA, USA.
authors.forename: Luciano H
authors.initials: LH
authors.lastname: Apponi
authors.affiliation: Department of Biochemistry, Emory University School of Medicine, Atlanta, GA, USA.
authors.forename: Ayan
authors.initials: A
authors.lastname: Banerjee
authors.affiliation: Department of Pharmacology, Emory University School of Medicine, Atlanta, GA, USA.
authors.forename: Grace K
authors.initials: GK
authors.lastname: Pavlath
authors.affiliation: Department of Biochemistry, Emory University School of Medicine, Atlanta, GA, USA.
authors.forename: Anita H
authors.initials: AH
authors.lastname: Corbett
keywords: PABPN1; alanine expansion; antibody; muscle disease; oculopharyngeal muscular dystrophy