title: Loss of plectin causes epidermolysis bullosa with muscular dystrophy: cDNA cloning and genomic organization.
abstract: Plectin is a widely expressed high molecular weight protein that is involved in cytoskeleton-membrane attachment in epithelial cells, muscle, and other tissues. The human autosomal recessive disorder epidermolysis bullosa with muscular dystrophy (MD-EBS) shows epidermal blister formation at the level of the hemidesmosome and is associated with a myopathy of unknown etiology. Here, plectin was found to be absent in skin and cultured keratinocytes from an MD-EBS patient by immunofluorescence and immunoprecipitation, suggesting that plectin is a candidate gene/protein system for MD-EBS mutation. The 14800-bp human plectin cDNA was cloned and sequenced. The predicted 518-kD polypeptide has homology to the actin-binding domain of the dystrophin family at the amino terminus, a central rod domain, and homology to the intermediate filament-associated protein desmoplakin at the carboxyl terminus. The corresponding human gene (PLEC1), consisting of 33 exons spanning >26 kb of genomic DNA was cloned, sequenced, and mapped to chromosomal band 8q24. Homozygosity by descent was observed in the consanguineous MD-EBS family with intragenic plectin polymorphisms. Direct sequencing of PCR-amplified plectin cDNA from the patient's keratinocytes revealed a homozygous 8-bp deletion in exon 32 causing a frameshift and a premature termination codon 42 bp downstream. The clinically unaffected parents of the proband were found to be heterozygous carriers of the mutation. These results establish the molecular basis of MD-EBS in this family and clearly demonstrate the important structural role for plectin in cytoskeleton-membrane adherence in both skin and muscle.
authors.affiliation: Department of Anatomy and Physiology, Medical Sciences Institute, University of Dundee, UK.
authors.forename: W H
authors.initials: WH
authors.lastname: McLean
authors.forename: L
authors.initials: L
authors.lastname: Pulkkinen
authors.forename: F J
authors.initials: FJ
authors.lastname: Smith
authors.forename: E L
authors.initials: EL
authors.lastname: Rugg
authors.forename: E B
authors.initials: EB
authors.lastname: Lane
authors.forename: F
authors.initials: F
authors.lastname: Bullrich
authors.forename: R E
authors.initials: RE
authors.lastname: Burgeson
authors.forename: S
authors.initials: S
authors.lastname: Amano
authors.forename: D L
authors.initials: DL
authors.lastname: Hudson
authors.forename: K
authors.initials: K
authors.lastname: Owaribe
authors.forename: J A
authors.initials: JA
authors.lastname: McGrath
authors.forename: J R
authors.initials: JR
authors.lastname: McMillan
authors.forename: R A
authors.initials: RA
authors.lastname: Eady
authors.forename: I M
authors.initials: IM
authors.lastname: Leigh
authors.forename: A M
authors.initials: AM
authors.lastname: Christiano
authors.forename: J
authors.initials: J
authors.lastname: Uitto
mesh_terms: D000199:Actins / Q000378:metabolism; D000328:Adult; D000595:Amino Acid Sequence; D001483:Base Sequence; D002874:Chromosome Mapping; D002898:Chromosomes, Human, Pair 8 / Q000235:genetics; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics*; D004820:Epidermolysis Bullosa / Q000150:complications* / Q000235:genetics* / Q000473:pathology; D005260:Female; D016368:Frameshift Mutation; D006801:Humans; D007381:Intermediate Filament Proteins / Q000172:deficiency* / Q000235:genetics*; D008297:Male; D008969:Molecular Sequence Data; D009136:Muscular Dystrophies / Q000150:complications* / Q000235:genetics* / Q000473:pathology; D010375:Pedigree; D010641:Phenotype; D051190:Plectin; D016133:Polymerase Chain Reaction
chemical_list: D000199:Actins; D018076:DNA, Complementary; D007381:Intermediate Filament Proteins; C495332:PLEC protein, human; D051190:Plectin