Expression of muscle-type phosphorylase in innervated and aneural cultured muscle of patients with myophosphorylase deficiency

Andrea Martinuzzi, Lodovica Vergani, Rosalba Carrozzo, Marina Fanin, Lucia Bartoloni, Corrado Angelini, Valerie Askanas, W. King Engel

Research output: Contribution to journalArticlepeer-review

Abstract

Patients with McArdle's myopathy lack muscle glycogen phosphorylase (M-GP) activity. Regenerating and cultured muscle of patients with McArdle's myopathy presents a glycogen phosphorylase (GP) activity, but it is not firmly established whether M-GP or non-M-GP isoforms are expressed. We have cultured myoblasts from biopsy specimen of five patients with McArdle's myopathy. Skeletal muscle was cultured aneurally or was innervated by coculture with fetal rat spinal cord expiants. In the patients' muscle biopsies and in their cultured innervated and aneural muscle we studied total GP activity, isoenzymatic pattern, reactivity with anti-M-GP antiserum, and presence of M-GP mRNA. There was no detectable enzymatic activity, no immunoreactivity with anti-M-GP antiserum, and no M-GP mRNA in the muscle biopsy of all patients. GP activity, M-GP isozyme, and anti-M-GP antiserum reactivity were present in patients' aneural cultures, increased after innervation, and were undistinguishable from control. M-GP mRNA was demonstrated in both aneural and innervated cultures of patients and control by primer extension and PCR amplification of total RNA. Our studies indicate that the M-GP gene is normally transcribed and translated in cul-tured muscle of patients with myophosphorylase deficiency.

Original languageEnglish
Pages (from-to)1774-1780
Number of pages7
JournalJournal of Clinical Investigation
Volume92
Issue number4
Publication statusPublished - 1993

Keywords

  • Glycogenosis type v
  • Human muscle glycogen phosphorylase
  • Muscle culture

ASJC Scopus subject areas

  • Medicine(all)

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