Clustering of COL7A1 Mutations in Exon 73: Implications for Mutation Analysis in Dystrophic Epidermolysis Bullosa

Mecklenbeck, Sabine; Hammami-Hauasli, Nadja; Höpfner, Bianca; Schumann, Hauke; kramer, Annika; Küster, Wolfgang; Bruckner‐Tuderman, Leena

doi:10.1046/j.1523-1747.1999.00518.x

Cited by 36 publications

(25 citation statements)

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“…Interestingly, co-expression of WT and G2015E-collagen VII, in which the glycine substitution is only three triplets away from G2006D, resulted in reduced thermal stability and a T m 34°C, but no accumulation in the endoplasmic reticulum. These observations are in keeping with genotype-phenotype correlation studies (28,29,17), which have not yielded a direct correlation between the thermal stability of collagen VII mutants and the DEB phenotype, although the relation between conformational heterogeneity of collagen VII and disease severity has not been mapped in a systematic manner.…”

Section: Discussionsupporting

confidence: 72%

Dominant-negative Effects of COL7A1 Mutations Can be Rescued by Controlled Overexpression of Normal Collagen VII

Fritsch

Spassov

Elfert

et al. 2009

Journal of Biological Chemistry

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Dominant-negative interference by glycine substitution mutations in the COL7A1 gene causes dominant dystrophic epidermolysis bullosa (DDEB), a skin fragility disorder with mechanically induced blistering. Although qualitative and quantitative alterations of the COL7A1 gene product, collagen VII, underlie DDEB, the lack of direct correlation between mutations and the clinical phenotype has rendered DDEB less amenable to therapeutic targeting. To delineate the molecular mechanisms of DDEB, we used recombinant expression of wildtype (WT) and mutant collagen VII, which contained a naturally occurring COL7A1 mutation, G1776R, G2006D, or G2015E, for characterization of the triple helical molecules. The mutants were co-expressed with WT in equal amounts and could form heterotrimeric hybrid triple helices, as demonstrated by affinity purification and mass spectrometry. The thermal stability of the mutant molecules was strongly decreased, as evident in their sensitivity to trypsin digestion. The helix-to-coil transition, T m , of the mutant molecules was 31-34°C, and of WT collagen VII 41°C. Co-expression of WT with G1776R-or G2006D-collagen VII resulted in partial intracellular retention of the collagen, and mutant collagen VII had reduced ability to support cell adhesion. Intriguingly, controlled overexpression of WT collagen VII gradually improved the thermal stability of the collective of collagen VII molecules. Co-expression in a ratio of 90% WT:10% mutant increased the T m to 41°C for G1776R-collagen VII and to 39°C for G2006D-and G2015E-collagen VII. Therefore, increasing the expression of WT collagen VII in the skin of patients with DDEB can be considered a valid therapeutic approach.Mutations in the collagen VII gene, COL7A1, cause dystrophic epidermolysis bullosa (DEB), 3 a heritable skin fragility disorder characterized by mechanically induced blistering of the skin and mucosa, and excessive scarring (1). DEB is classified into clinical subtypes with dominant or recessive inheritance (2), and so far more than 400 different COL7A1 mutations are known, which underlie a broad spectrum of clinical presentations. Collagen VII is the major molecular constituent of anchoring fibrils in the skin. These centro-symmetrically banded fibrils extend from the epidermal basement membrane into the underlying dermal stroma and connect the epidermis to the dermis. Collagen VII is synthesized as three identical pro-␣1(VII) polypeptide chains, which are hydroxylated and glycosylated in a coordinated manner and then fold into triple-helical procollagen VII in the endoplasmic reticulum (ER). The procollagen, which contains a central collagenous triple-helix flanked by two non-collagenous domains, NC-1 and NC-2, is secreted into the extracellular space, where the C-terminal NC-2 propeptide is proteolytically removed by bone morphogenetic protein-1 (3). Subsequently, mature collagen VII undergoes a multistep fibril polymerization process to form the anchoring fibrils (4).The pathology in DDEB has been thought to result from negative ...

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Section: Discussionsupporting

confidence: 72%

Dominant-negative Effects of COL7A1 Mutations Can be Rescued by Controlled Overexpression of Normal Collagen VII

Fritsch

Spassov

Elfert

et al. 2009

Journal of Biological Chemistry

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“…Indeed, exon 73 has previously been shown to harbour a large number of glycine substitutions, including de novo mutations. De novo glycine substitutions resulting in DDEB are rare but the following mutations have been reported: G1775D, G2067R (40), G2012S (8), G2012D (55), G2028R (56), G2040V (54), G2043R, G2043W (57), G2076D (58), G2079E (52) and G2348R (59). The de novo mutations usually result from glycine substitutions and are seen in DDEB, but Posteraro et al.…”

Section: De Novo Mutationsmentioning

confidence: 99%

Mutation analysis and characterization of COL7A1 mutations in dystrophic epidermolysis bullosa

Dang

Murrell

2008

Experimental Dermatology

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Dystrophic epidermolysis bullosa (DEB) is inherited in both an autosomal dominant DEB and autosomal recessive manner RDEB, both of which result from mutations in the type VII collagen gene (COL7A1). To date, 324 pathogenic mutations have been detected within COL7A1 in different variants of DEB; many mutations are clustered in exon 73 (10.74%) which is close to the 39 amino acid interruption region. Dominant dystrophic epidermolysis bullosa usually involves glycine substitutions within the triple helix of COL7A1 although other missense mutations, deletions or splice-site mutations may underlie some cases. In recessive dystrophic epidermolysis bullosa, the mutations include nonsense, splice site, deletions or insertions, 'silent' glycine substitutions within the triple helix and non-glycine missense mutations within the triple helix or non-collagenous NC-2 domain. The nature of mutations in COL7A1 and their positions correlate reasonably logically with the severity of the resulting phenotypes.Key words: COL7A1 -dystrophic epidermolysis bullosamutation Please cite this paper as: Mutation analysis and characterization of COL7A1 mutations in dystrophic epidermolysis bullosa. Experimental Dermatology 2008; 17: 553-568.

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“…Si les substitutions de glycine ont déjà été rapportées à 79 reprises dans des cas d'EBDD (parmi 132 mutations non-sens ou faux sens dans le gène COL 7A1), elles sont rarement rapportées comme étant survenues de novo. Par ailleurs, seuls trois cas (en dehors du cas décrit ici) sont liés à des substitutions de glycine par un tryptophane, dont deux survenues de novo et un hérité [7][8][9]. La mutation fauxsens G 1776W dans l'exon 61, quant à elle, n'a encore jamais été décrite.…”

Section: Discussionunclassified

Épidermolyse bulleuse dystrophique localisée dominante de novo

Bursztejn

Pinault

Louarn

et al. 2008

Annales de Dermatologie et de Vénéréologie

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Clustering of COL7A1 Mutations in Exon 73: Implications for Mutation Analysis in Dystrophic Epidermolysis Bullosa

Cited by 36 publications

References 14 publications

Dominant-negative Effects of COL7A1 Mutations Can be Rescued by Controlled Overexpression of Normal Collagen VII

Dominant-negative Effects of COL7A1 Mutations Can be Rescued by Controlled Overexpression of Normal Collagen VII

Mutation analysis and characterization of COL7A1 mutations in dystrophic epidermolysis bullosa

Épidermolyse bulleuse dystrophique localisée dominante de novo

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