title: Abnormal expression of RNA polymerase II-associated proteins in muscle of patients with myofibrillar myopathies.
abstract: OBJECTIVE
  Myofibrillar myopathies (MFMs) are a group of inherited or sporadic neuromuscular disorders characterized morphologically by foci of myofibril dissolution, disintegration of the Z-disk and insoluble protein aggregates within the muscle fibres. The sequential events leading to muscle fibre damage remains largely unknown.
  
  
  RESULTS
  We investigated the expression and the cellular localization of RNA polymerase II (RNAPII)-associated proteins (RPAPs) in muscle biopsies from patients with genetically proven and sporadic MFMs. Our data demonstrated that RPAP2, and to a lesser extent GPN1/RPAP4, are accumulated focally in the cytoplasm of MFM muscle fibres in which they co-localize with POLR2A/RPB1, the largest subunit of RNAPII, and correspond to αB-cystallin deposits in distribution and staining intensity. No abnormal staining for RPAP2 has been observed in muscle of patients with central cores, minicores and neurogenic target fibres.
  
  
  CONCLUSIONS
  Together, these findings could provide new insights into the molecular pathogenesis of MFMs and suggest that RPAP2 immunostaining can be a useful diagnostic tool to depict protein aggregates in MFMs.
authors.affiliation: Department of Neurological and Movement Sciences, Section of Clinical Neurology, University of Verona, Verona, Italy.
authors.forename: Valeria
authors.initials: V
authors.lastname: Guglielmi
authors.affiliation: Department of Neurological and Movement Sciences, Section of Clinical Neurology, University of Verona, Verona, Italy.
authors.forename: Matteo
authors.initials: M
authors.lastname: Marini
authors.affiliation: Institut de Recherches Cliniques de Montréal (IRCM), Montréal, QC, Canada.
authors.forename: Émilie Fiola
authors.initials: ÉF
authors.lastname: Masson
authors.affiliation: Department of Neurological and Movement Sciences, Section of Anatomy and Histology, University of Verona, Verona, Italy.
authors.forename: Manuela
authors.initials: M
authors.lastname: Malatesta
authors.affiliation: Institut de Recherches Cliniques de Montréal (IRCM), Montréal, QC, Canada.
authors.forename: Diane
authors.initials: D
authors.lastname: Forget
authors.affiliation: Department of Neurological and Movement Sciences, Section of Clinical Neurology, University of Verona, Verona, Italy.
authors.forename: Giuliano
authors.initials: G
authors.lastname: Tomelleri
authors.affiliation: Institut de Recherches Cliniques de Montréal (IRCM), Montréal, QC, Canada.
authors.forename: Benoit
authors.initials: B
authors.lastname: Coulombe
authors.affiliation: Department of Neurological and Movement Sciences, Section of Clinical Neurology, University of Verona, Verona, Italy.
authors.forename: Gaetano
authors.initials: G
authors.lastname: Vattemi
mesh_terms: D002352:Carrier Proteins / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism* / Q000473:pathology; D020914:Myopathies, Structural, Congenital / Q000378:metabolism* / Q000473:pathology; D012319:RNA Polymerase II / Q000378:metabolism*
chemical_list: D002352:Carrier Proteins; C571028:RPAP2 protein, human; D012319:RNA Polymerase II
keywords: RNA polymerase II (RNAPII); RNA polymerase II associated proteins (RPAPs); myofibrillar myopathies; protein aggregates