BACKGROUND: Epidermolysis bullosa simplex (EBS) is an inherited skin disorder caused by mutations in the keratin 5 (KRT5) and keratin 14 (KRT14) genes, with fragility of basal keratinocytes leading to epidermal cytolysis and blistering. OBJECTIVES: In this study, we characterized mutations in KRT5 and KRT14 genes in patients with EBS and investigated their possible structure-function correlations. MATERIALS AND METHODS: Mutations were characterized using polymerase chain reaction (PCR) and DNA sequencing. Further, to explore possible correlations with function, the structural effects of the mutations in segment 2B of KRT5 and KRT14 and associated with EBS in our patients, as well as those reported previously, were modelled by molecular dynamics with the aid of the known crystal structure of the analogous segment of human vimentin. RESULTS: We have identified mutations in the KRT5 and KRT14 genes in 16 of 23 families affected by EBS in the Czech Republic. Eleven different sequence variants were found, of which four have not been reported previously. Novel mutations were found in two patients with the EBS-Dowling-Meara variant (EBS-DM) [KRT14-p.Ser128Pro and KRT14-p.Gln374_Leu387dup(14)] and in three patients with localized EBS (KRT14-p.Leu136Pro and KRT5-p.Val143Ala). Molecular dynamics studies show that the mutations p.Glu411del and p.Ile467Thr perturb the secondary alpha-helical structure of the mutated polypeptide chain, the deletion p.Glu411del in KRT14 has a strong but only local influence on the secondary structure of KRT14, and the structural impact of the mutation p.Ile467Thr in KRT5 is spread along the helix to the C-terminus. In all the other point mutations studied, the direct structural impact was significantly weaker and did not destroy the alpha-helical pattern of the secondary protein structure. The changes of 3-D structure of the KRT5/KRT14 dimer induced by the steric structural impact of the single point mutations, and the resulting altered inter- and intramolecular contacts, are spread along the protein helices to the protein C-terminus, but the overall alpha-helical character of the secondary structure is not destroyed and the atomic displacements induced by mutations cause only limited-scale changes of the quaternary structure of the dimer. CONCLUSIONS: The results of molecular modelling show relationships between patients' phenotypes and the structural effects of individual mutations.

• MeSH
• dítě MeSH
• dospělí MeSH
• epidermolysis bullosa simplex genetika   patologie   MeSH
• fenotyp MeSH
• fluorescenční mikroskopie MeSH
• genetická predispozice k nemoci MeSH
• intermediární filamenta ultrastruktura   MeSH
• keratin-14 genetika   MeSH
• keratin-5 genetika   MeSH
• kůže ultrastruktura   MeSH
• lidé MeSH
• molekulární modely MeSH
• mutace MeSH
• předškolní dítě MeSH
• Check Tag
• dítě MeSH
• dospělí MeSH
• lidé MeSH
• mužské pohlaví MeSH
• předškolní dítě MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The hypodactylous (hd) locus impairs limb development and spermatogenesis, leading to male infertility in rats. We show that the hd mutation is caused by an insertion of an endogenous retrovirus into intron 10 of the Cntrob gene. The retroviral insertion in hd mutant rats disrupts the normal splicing of Cntrob transcripts and results in the expression of a truncated protein. During the final phase of spermiogenesis, centrobin localizes to the manchette, centrosome, and the marginal ring of the spermatid acroplaxome, where it interacts with keratin 5-containing intermediate filaments. Mutant spermatids show a defective acroplaxome marginal ring and separation of the centrosome from its normal attachment site of the nucleus. This separation correlates with a disruption of head-tail coupling apparatus, leading to spermatid decapitation during the final step of spermiogenesis and the absence of sperm in the epididymis. Cntrob may represent a novel candidate gene for presently unexplained hereditary forms of teratozoospermia and the "easily decapitated sperm syndrome" in humans.

• MeSH
• bičík spermie metabolismus   MeSH
• blotting far-western MeSH
• centrozom metabolismus   MeSH
• elektronová mikroskopie MeSH
• endogenní retroviry genetika   MeSH
• epididymis metabolismus   MeSH
• fluorescenční protilátková technika MeSH
• hlavička spermie metabolismus   MeSH
• homeoboxové geny genetika   MeSH
• homeodoménové proteiny metabolismus   MeSH
• introny genetika   MeSH
• keratin-5 genetika   metabolismus   MeSH
• krysa rodu rattus MeSH
• mutace genetika   MeSH
• mužská infertilita genetika   metabolismus   MeSH
• polymerázová řetězová reakce s reverzní transkripcí MeSH
• proteiny buněčného cyklu fyziologie   MeSH
• spermatidy metabolismus   MeSH
• spermatogeneze genetika   MeSH
• transport proteinů genetika   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• práce podpořená grantem MeSH