Erratum: Using Diffuse Scattering to Observe X-Ray-Driven Nonthermal Melting [Phys. Rev. Lett. 126, 015703 (2021)]

This corrects the article DOI: 10.1103/PhysRevLett.126.015703.

Using Diffuse Scattering to Observe X-Ray-Driven Nonthermal Melting

We present results from the SPring-8 Angstrom Compact free electron LAser facility, where we used a high intensity (∼10^{20}  W/cm^{2}) x-ray pump x-ray probe scheme to observe changes in the ionic structure of silicon induced by x-ray heating of the electrons. By avoiding Laue spots in the scattering signal from a single crystalline sample, we observe a rapid rise in diffuse scattering and a transition to a disordered, liquidlike state with a structure significantly different from liquid silicon. The disordering occurs within 100 fs of irradiation, a timescale that agrees well with first principles simulations, and is faster than that predicted by purely inertial behavior, suggesting that both the phase change and disordered state reached are dominated by Coulomb forces. This method is capable of observing liquid scattering without masking signal from the ambient solid, allowing the liquid structure to be measured throughout and beyond the phase change.

Self-generated surface magnetic fields inhibit laser-driven sheath acceleration of high-energy protons

High-intensity lasers interacting with solid foils produce copious numbers of relativistic electrons, which in turn create strong sheath electric fields around the target. The proton beams accelerated in such fields have remarkable properties, enabling ultrafast radiography of plasma phenomena or isochoric heating of dense materials. In view of longer-term multidisciplinary purposes (e.g., spallation neutron sources or cancer therapy), the current challenge is to achieve proton energies well in excess of 100 MeV, which is commonly thought to be possible by raising the on-target laser intensity. Here we present experimental and numerical results demonstrating that magnetostatic fields self-generated on the target surface may pose a fundamental limit to sheath-driven ion acceleration for high enough laser intensities. Those fields can be strong enough (~10⁵ T at laser intensities ~10²¹ W cm^–2) to magnetize the sheath electrons and deflect protons off the accelerating region, hence degrading the maximum energy the latter can acquire.

Laser-generated ion acceleration has received increasing attention due to recent progress in super-intense lasers. Here the authors demonstrate the role of the self-generated magnetic field on the ion acceleration and limitations on the energy scaling with laser intensity.

Scintillator-based transverse proton beam profiler for laser-plasma ion sources

A high repetition rate scintillator-based transverse beam profile diagnostic for laser-plasma accelerated proton beams has been designed and commissioned. The proton beam profiler uses differential filtering to provide coarse energy resolution and a flexible design to allow optimisation for expected beam energy range and trade-off between spatial and energy resolution depending on the application. A plastic scintillator detector, imaged with a standard 12-bit scientific camera, allows data to be taken at a high repetition rate. An algorithm encompassing the scintillator non-linearity is described to estimate the proton spectrum at different spatial locations.

Landscape of genetic lesions in 944 patients with myelodysplastic syndromes

High-throughput DNA sequencing significantly contributed to diagnosis and prognostication in patients with myelodysplastic syndromes (MDS). We determined the biological and prognostic significance of genetic aberrations in MDS. In total, 944 patients with various MDS subtypes were screened for known/putative mutations/deletions in 104 genes using targeted deep sequencing and array-based genomic hybridization. In total, 845/944 patients (89.5%) harbored at least one mutation (median, 3 per patient; range, 0-12). Forty-seven genes were significantly mutated with TET2, SF3B1, ASXL1, SRSF2, DNMT3A, and RUNX1 mutated in >10% of cases. Many mutations were associated with higher risk groups and/or blast elevation. Survival was investigated in 875 patients. By univariate analysis, 25/48 genes (resulting from 47 genes tested significantly plus PRPF8) affected survival (P<0.05). The status of 14 genes combined with conventional factors revealed a novel prognostic model ('Model-1') separating patients into four risk groups ('low', 'intermediate', 'high', 'very high risk') with 3-year survival of 95.2, 69.3, 32.8, and 5.3% (P<0.001). Subsequently, a 'gene-only model' ('Model-2') was constructed based on 14 genes also yielding four significant risk groups (P<0.001). Both models were reproducible in the validation cohort (n=175 patients; P<0.001 each). Thus, large-scale genetic and molecular profiling of multiple target genes is invaluable for subclassification and prognostication in MDS patients.

Tunable radiation source by coupling laser-plasma-generated electrons to a periodic structure

Near-infrared radiation around 1000 nm generated from the interaction of a high-density MeV electron beam, obtained by impinging an intense ultrashort laser pulse on a solid target, with a metal grating is observed experimentally. Theoretical modeling and particle-in-cell simulation suggest that the radiation is caused by the Smith-Purcell mechanism. The results here indicate that tunable terahertz radiation with tens GV/m field strength can be achieved by using appropriate grating parameters.

Fast focusing of short-pulse lasers by innovative plasma optics toward extreme intensity

We developed a compact plasma-based focusing optic that, in one step, increases the peak intensity of ultrahigh-intensity lasers without modifying the laser system itself. By using a plasma-based focusing optic with extremely small f-number (f/0.4), we have experimentally demonstrated a fivefold reduction of the focal spot size (from 4.4 to 0.9 microm), thus producing an at least eightfold enhancement of the laser light intensity. This innovative plasma-based optic opens the way for the study of high-energy-density and high-field science at intensities greater than presently available.

Alterations in endogenous nitric oxide production after cardiopulmonary bypass in lambs with normal and increased pulmonary blood flow

BACKGROUND

After cardiopulmonary bypass (CPB), altered vascular reactivity is a major source of complications, particularly for children with increased pulmonary blood flow. Although changes in agonist-induced NO activity are well described after CPB, potential changes in basal NO production and their role in post-CPB pulmonary hypertension remain unclear. By using aortopulmonary vascular graft placement in the fetal lamb (shunt lambs), we established a unique model of pulmonary hypertension that mimics congenital heart disease with increased pulmonary blood flow. The objective of the present study was to investigate potential alterations in endogenous NO production after CPB in lambs with normal and increased pulmonary blood flow.

METHODS AND RESULTS

Vascular pressures and blood flows were monitored in 1-month-old lambs (n=7) with increased pulmonary blood flow and 6 age-matched control lambs. After shunt closure, hypothermic CPB (25 degrees C) was performed for 2 hours. The hemodynamic variables were monitored for 4 hours after CPB. Before, during, and after CPB, peripheral lung biopsies were performed to determine tissue NO, nitrite, nitrate, and cGMP concentrations; total NO synthase (NOS) activity; and endothelial NOS protein levels. Hypothermic CPB increased both mean pulmonary arterial pressure and left pulmonary vascular resistance (P:<0.05). The increase in pulmonary arterial pressure induced in shunt lambs was greater than that induced in control lambs (P:<0.05). Four hours after CPB, tissue concentrations of NO, nitrite, nitrate, and cGMP were decreased to approximately 70% of pre-CPB levels in both control and shunt lambs (P:<0.05). Total NOS activity and endothelial NOS protein levels were unchanged.

CONCLUSIONS

Modest decreases in basal NO production, the inability to increase NO production, or both may play a role in the altered pulmonary vascular reactivity after CPB. The decrease in NO is independent of gene expression. However, other mechanisms for this decrease, such as substrate or cofactor availability, warrant further study.

Expression vector with DNA of bovine papilloma virus 1 for keratinocyte gene therapy

Although there are several methods for introducing the genes to keratinocytes in vivo, expression of transgene does not last long enough for effective keratinocyte gene therapy. In this study, we added bovine papilloma virus 1 (BPV) DNA into expression vectors with the lacZ gene driven by metallothionein and keratin 10 promoters, and we transferred them into keratinocytes in vivo using the naked DNA method, and measured beta-gal activity in keratinocytes. The results showed that beta-galactosidase activity of vectors with the BPV DNA was clearly higher than that without the DNA. Moreover, time-course experiment disclosed that the activity of the BPV vector declined at a lower rate than that of the control vector, suggesting this fragment prolonged transgene expression. These results should prove useful for understanding gene regulation in keratinocytes in vivo and for developing potential expression vectors for keratinocyte gene therapy.

In vivo gene introduction into keratinocytes using jet injection

Successful keratinocyte gene therapy requires the development of efficient methods of gene transfer to keratinocytes. Jet injection of a solution containing DNA can be used to transfer genes to several tissues in vivo. In this article, we tried to introduce DNA into rat and human keratinocytes using this method. First, we fired a beta-gal expression vector into rat skin at several distances using a jet injector and examined beta-gal activity in the epidermal keratinocytes. The highest activity in keratinocytes was found when the plasmid was fired at 10 cm from the skin surface; the activity lessened as the firing distance became shorter than 10 cm. Next, we transplanted human skin on to a nude rat, fired the vector into the human skin from a distance of 10 cm and examined the beta-gal activity. We also injected the same amount of plasmid with a needle to compare jet with needle injections. The results showed that jet injection of the naked DNA could introduce and express DNA in human keratinocytes in vivo and that jet injection exhibited much higher activity than needle injection. Jet injection of the naked DNA will provide a method for keratinocyte gene therapy in the future.

Nuclear factor-kappa B mediates TNF-alpha inhibitory effect on alpha 2(I) collagen (COL1A2) gene transcription in human dermal fibroblasts

Among its plethora of activities as an inflammatory mediator, TNF-alpha has potent regulatory control on extracellular matrix production and degradation. Earlier studies have documented that TNF-alpha inhibits type I collagen gene (COL1A2) expression at the transcriptional level, but the characterization of the transcription factors involved has been elusive. In the present study, using transient cell transfection of human dermal fibroblasts with a battery of 5' end deletion/chloramphenicol acetyltransferase (CAT) reporter gene constructs, we have characterized the TNF-alpha response element of the COL1A2 promoter. The TNF-alpha response element was attributed to a specific region that comprises noncanonical activator protein-1 (AP-1) (CGAGTCA) and NF-kappa B (AGAGTTTCCC) binding sites. TNF-alpha effect was eliminated by a 2-bp substitution mutation in the NF-kappa B1 binding half site of the NF-kappa B cis element. Electrophoretic mobility shift assays (EMSA) showed that recombinant human NF-kappa B heterodimers as well as NF-kappa B1 and RelA homodimers, but not AP-1, were capable of binding this element. Further, EMSA with human fibroblast nuclear extracts demonstrated enhanced binding of a single, specific complex within 5 min of TNF-alpha stimulation, which reached a plateau by 1 h and was not affected by preincubation of cells with cycloheximide. Gel supershift assays identified the complex as the NF-kappa B (p50/p65) heterodimer, whereas Abs to nuclear factor of activated T cells (NF-AT) and Jun family members failed to recognize the complex. These data suggest that in fibroblasts TNF-alpha activates and initiates the nuclear translocation of NF-kappa B that binds a divergent NF-kappa B element and plays a critical role in the observed inhibition of alpha 2(I) collagen gene transcription.

Diagnostic dilemma of "sporadic" cases of dystrophic epidermolysis bullosa: a new dominant or mitis recessive mutation?

Dystrophic forms of epidermolysis bullosa (DEB), characterized by mutations in the type VII collagen gene (COL7A1), are inherited either in an autosomal dominant or autosomal recessive fashion, and sporadic, de novo cases have also been reported. Clinically, the dominant forms (DDEB) can be indistinguishable from the mild, mitis forms of recessively inherited DEB (M-RDEB). This situation poses a dilemma in case of families with 1 mildly affected individual and clinically normal parents: Is it a new dominant or mitis recessive DEB? In this study we review 2 cases with mild DEB, the parents being clinically normal. One of the cases was shown to be a compound heterozygote for 2 silent missense mutations (R2063W/G2366S), thus being diagnosed as M-RDEB. The second case had a single glycine substitution mutation (G2079E) in COL7A1 and had therefore DDEB. These findings have implications for the genetic counseling of these families concerning the risk of recurrence of the disease in subsequent pregnancies in the present and future generations.

Cooperation between SMAD and NF-kappaB in growth factor regulated type VII collagen gene expression

We have previously demonstrated that transforming growth factor-beta (TGF-beta) and pro-inflammatory cytokines, such as tumor necrosis factor-alpha (TNF-alpha) or interleukin-1beta, synergistically enhance the expression of type VII collagen gene (COL7A1) in human dermal fibroblasts in culture (Mauviel et al., 1994). Recently, we identified a SMAD-containing complex, rapidly induced by TGF-beta and binding the region [-496/-444] of the COL7A1 promoter, responsible for COL7A1 gene transactivation (Vindevoghel et al., 1998a). In this report, we demonstrate that TGF-beta and TNF-alpha response elements are distinct entities within the COL7A1 promoter. In particular, we demonstrate that the TNF-alpha effect is mediated by NF-kappaB1/RelA (p50/p65) and RelA/RelA (p65/p65) NF-kappaB complexes binding the TNF-alpha response element (TaRE) located in the region [-252/-230], with RelA acting as the transcriptional activator. Finally, we provide definitive evidence for the role of both TGF-beta and TNF-alpha response elements as enhancer sequences, functioning in the context of a heterologous promoter in an additive manner in response to TGF-beta and TNF-alpha. This study provides the first identification of a functional interaction between the two immediate-early transcription factors, SMAD and NF-kappaB, to activate the expression of an extracellular matrix-related gene, COL7A1.

SMAD3/4-dependent transcriptional activation of the human type VII collagen gene (COL7A1) promoter by transforming growth factor beta

The human type VII collagen gene (COL7A1) recently has been identified as an immediate-early response gene for transforming growth factor beta (TGF-beta)/SMAD signaling pathway. In this study, by using MDA-MB-468 SMAD4-/- breast carcinoma cells, we demonstrate that expression of SMAD4 is an absolute requirement for SMAD-mediated promoter activity. We also demonstrate that the SMAD binding sequence (SBS) representing the TGF-beta response element in the region -496/-444 of the COL7A1 promoter functions as an enhancer in the context of a heterologous promoter. Electrophoretic mobility-shift assays with nuclear extracts from COS-1 cells transfected with expression vectors for SMADs 1-5 indicate that SMAD3 forms a complex with a migration similar to that of the endogenous TGF-beta-specific complex observed in fibroblast extracts. Electrophoretic mobility-shift assays using recombinant glutathione S-transferase-SMAD fusion proteins indicate that both SMAD4 and C-terminally truncated SMAD3, but not SMAD2, can bind the COL7A1 SBS. Coexpression of SMAD3 and SMAD4 in COS-1 cells leads to the formation of two complexes: a DNA/protein complex containing SMAD3 alone and another slower-migrating complex containing both SMAD3 and SMAD4, the latter complex not being detected in fibroblasts. Maximal transactivation of COL7A1 SBS-driven promoters in either MDA-MB-468 carcinoma cells or fibroblasts requires concomitant overexpression of SMAD3 and SMAD4. These data may represent the first identification of a functional homomeric SMAD3 complex regulating a human gene.

Novel COL7A1 mutations in dystrophic forms of epidermolysis bullosa

Mutations in the type VII collagen gene (COL7A1) have been shown to underlie different variants of dystrophic epidermolysis bullosa (DEB). Examination of the genetic database indicates that most of the mutations are family specific, with few recurrent mutations. To facilitate further refinement of genotype/phenotype correlations in DEB, we have examined a cohort of nine families with DEB (seven recessively and two dominantly inherited) by a mutation detection strategy based on polymerase chain reaction amplification of COL7A1 genomic sequences, followed by heteroduplex scanning and direct nucleotide sequencing. The results revealed 16 allelic mutations, 11 of them being novel, previously unpublished. The genetic information was also used for prenatal testing in a family at risk for recurrence of a severe, Hallopeau-Siemens type of RDEB. These data contribute to the expanding database of COL7A1 mutations in DEB.

Smad-dependent transcriptional activation of human type VII collagen gene (COL7A1) promoter by transforming growth factor-beta

We have previously shown that transforming growth factor-beta (TGF-beta) increases type VII collagen gene (COL7A1) expression in human dermal fibroblasts in culture (Mauviel, A., Lapière, J.-C., Halcin, C., Evans, C. H., and Uitto, J. (1994) J. Biol. Chem. 269, 25-28). To gain insight into the molecular mechanisms underlying the up-regulation of COL7A1 by this growth factor, we performed transient cell transfections with a series of 5'-deletion promoter/chloramphenicol acetyltransferase reporter gene constructs. We identified a 68-base pair region between nucleotides -524 and -456, relative to the transcription start site, as critical for TGF-beta response. Using electrophoresis mobility shift assays (EMSAs) with an oligonucleotide spanning the region from -524 to -444, we discovered that a TGF-beta-specific protein-DNA complex was formed as early as 11 min after TGF-beta stimulation and persisted for 1 h after addition of the growth factor. Deletion analysis of the TGF-betaresponsive region of the COL7A1 promoter by EMSA identified segment -496/-444 as the minimal fragment capable of binding the TGF-beta-induced complex. Furthermore, two distinct segments, -496/-490 and -453/-444, appeared to be necessary for TGF-beta-induced DNA binding activity, suggesting a bipartite element. Supershift experiments with a pan-Smad antibody unambiguously identified the TGF-beta-induced complex as containing a Smad member. This is the first direct identification of binding of endogenous Smad proteins to regulatory sequences of a human gene.

Laminin 5 genes and Herlitz junctional epidermolysis bullosa: novel mutations and polymorphisms in the LAMB3 and LAMC2 genes. Mutations in brief no. 190. Online

Herlitz junctional epidermolysis bullosa (H-JEB; OMIM #226700) is a lethal, autosomal recessive blistering disorder characterized by fragility of the skin and other specialized epithelia. Previously, mutations in the laminin 5 genes (LAMA3, LAMB3, and LAMC2) have been disclosed, most of them in LAMB3. In this study, we have examined the genetic basis of H-JEB in three families utilizing heteroduplex analysis and automated nucleotide sequencing. In one family, the proband was compound heterozygote for previously unpublished LAMB3 mutations, 1482delC and W95X. In two other families, the probands were found to be homozygous for novel nonsense mutations C553X and K822X in the LAMC2 gene. These mutations result in premature termination codons and predict truncation of the corresponding polypeptides. Also, during the search of laminin 5 mutations, 18 LAMB3 and LAMC2 polymorphisms were discovered, 9 of them being previously undescribed. Delineation of novel homozygous nonsense mutations in the LAMB3 and LAMC2 genes, with previous demonstrations of LAMA3 mutations, re-emphasizes the concept that stop codon mutations in both alleles of any of the three laminin 5 genes result in the severe H-JEB phenotype.

Novel glycine substitution mutations in COL7A1 reveal that the Pasini and Cockayne-Touraine variants of dominant dystrophic epidermolysis bullosa are allelic

Mutations in the type VII collagen gene (COL7A1) have been shown to underlie dystrophic epidermolysis bullosa (DEB). The dominantly inherited forms of DEB have been divided into two clinical subcategories, the Pasini (DDEB-P) and the Cockayne-Touraine (DDEB-CT) variants, on the basis of the presence or absence of albopapuloid lesions. In this study, we have examined the molecular basis of DDEB in two Japanese families, one with DDEB-P and the other with DDEB-CT. Mutation detection strategy consisted of polymerase chain reaction amplification of COL7A1 from genomic DNA, followed by heteroduplex analysis and direct nucleotide sequencing. The results revealed heterozygous glycine substitution mutations, G2076D and G2034R, in these families, respectively. Thus, these two variants of DDEB are allelic, and subtle differences in the clinical presentation may reflect the precise position of the mutation along the type VII collagen molecule. Alternatively, the nature of the substituting amino acid (D versus R) may influence the clinical phenotype. This is the first demonstration of a COL7A1 mutation in DDEB-P, and brings the total number of dominant DEB variants with underlying glycine substitutions in COL7A1 to five, including the pretibial and localized variants as well as the Bart's syndrome, in addition to DDEB-P and DDEB-CT.

Immunohistochemical, ultrastructural, and molecular features of Kindler syndrome distinguish it from dystrophic epidermolysis bullosa

BACKGROUND

Kindler syndrome is a rare, inherited skin disease characterized by acral bullae formation, fusion of fingers and toes, and generalized progressive poikiloderma. The purpose of this study was to clarify the nature of the bullous component of Kindler syndrome and to determine whether this inherited skin disorder represents a variant of dystrophic epidermolysis bullosa or a unique independent clinical entity.

OBSERVATIONS

Two unrelated patients with Kindler syndrome were studied. Electron microscopy demonstrated marked duplication of the lamina densa, and clefts were observed in areas where the lamina densa was destroyed or obscured. Hemidesmosomes and anchoring fibrils showed normal features. Indirect immunofluorescence revealed normal linear labeling with antibodies against hemidesmosomal components (alpha 6 and beta 4 integrins, BPAG1, and BPAG2) and against anchoring filament components such as uncein, as detected by the 19-DEJ-1 monoclonal antibody. However, antibodies against the 3 respective laminin 5 chains, type IV collagen, and various type VII collagen epitopes (the aminoterminal NC1 domain, the central triple helical collagenous domain, and the carboxyterminal end of the triple helical collagenous domain) revealed a broad reticular staining pattern. Molecular screening of the type VII collagen gene (COL7A1) in the patients and their parents by heteroduplex analysis failed to detect any band shifts indicative of pathologic mutations.

CONCLUSIONS

These results suggest that the bullous component of Kindler syndrome is distinct from dystrophic epidermolysis bullosa caused by mutations in the type VII collagen gene. Additionally, the differential distribution patterns of uncein and laminin 5 in the patients' skin samples support the hypothesis that uncein and laminin 5 are different molecules.

Body mass index variations by age and sex, and prevalence of overweight in Japanese adults

OBJECTIVE

To determine the reference value of BMI for Japanese subjects and to estimate the prevalence of overweight based on this reference value.

DESIGN

Epidemiological analysis with the LMS method, which provides a way of obtaining normalized BMI distributions.

SUBJECTS

7508 Japanese subjects aged 18-69 y in 1993.

MEASUREMENTS

Height, age and body weight.

CALCULATION

BMI was calculated and tables for percentiles of BMI were plotted against age and sex. Furthermore, the prevalence of overweight was estimated based on 85th percentile of BMI in the men and women 20-29 y of age, who were considered the reference group.

RESULTS

The geometric mean BMI and the prevalence of overweight in men was highest in the 30-39 y age group. For women the maximum BMI and prevalence of overweight occurred in the decade 50-59 y. The cut-off points for overweight in this sample were 24.7 kg/m2 for men and 22.6 kg/m2 for women. These are considerably lower than the figures of 27.8 kg/m2 and 27.3 kg/m2 estimated for Americans.

CONCLUSIONS

The prevalence of obesity in Japanese populations should be estimated using ethnic specific values of BMI, rather than those drawn from Caucasians who tend to have higher BMI in each age group. The prevalence of overweight is increased as age increased in both sexes, especially in women.

Immunohistochemical analysis of the skin in junctional epidermolysis bullosa using laminin 5 chain specific antibodies is of limited value in predicting the underlying gene mutation

The anchoring filament protein laminin 5 is composed of three polypeptide chains (alpha 3, beta 3 and gamma 2) each encoded by separate genes (LAMA3, LAMB3 and LAMC2, respectively). Mutations in any of these three genes may give rise to the autosomal recessive blistering skin disease, junctional epidermolysis bullosa. At present, there is no easy way of predicting which of these three genes might harbour the pathogenetic laminin 5 mutations in a case of junctional epidermolysis bullosa. In this study, we assessed whether immunohistochemistry might be helpful in this regard. We performed immunohistochemical labelling of the dermal-epidermal junction using alpha 3, beta 3 and gamma 2 chain-specific antibodies in 11 patients with junctional epidermolysis bullosa, in whom the laminin 5 mutations had been previously delineated. Although, labelling for the laminin 5 chain bearing the mutations was attenuated or undetectable in all cases, a complete absence of labelling or a reduction in the staining intensity for the other two chains was also seen in all cases. The results showed that immunohistochemical labelling of the dermal-epidermal junction using alpha 3, beta 3 and gamma 2 chain-specific antibodies is not a specific indicator for which of the laminin 5 chain genes contains the pathogenetic mutations, and is therefore unreliable in screening for individual laminin 5 gene mutations in cases of junctional epidermolysis bullosa.

Glycine substitution mutations in the type VII collagen gene (COL7A1) in dystrophic epidermolysis bullosa: implications for genetic counseling

Dystrophic epidermolysis bullosa (DEB) is an inherited mechanobullous disorder characterized by fragility of the skin and mucous membranes. The anchoring fibril protein, type VII collagen, is encoded by COL7A1, which harbors mutations in this group of diseases. In this study, we report novel glycine substitution mutations in COL7A1 in two Japanese families with DEB. The mutation detection strategy consisted of PCR amplification of genomic DNA, followed by heteroduplex analysis and nucleotide sequencing of the PCR products demonstrating altered mobility. The first case is a patient with clinically severe recessive DEB. The proband was shown to have a homozygous glycine-to-valine substitution (G2671V) in exon 108. The clinically unaffected parents were heterozygous carriers of this mutation, indicating that this glycine substitution in one allele is "silent" when combined with a normal COL7A1 allele. Thus, this patient appeared to be affected with DEB inherited in an autosomal recessive pattern. The second case was a DEB patient with a heterozygous glycine-to-glutamic acid substitution (G2079E) in exon 75. The parents were clinically unaffected and neither had this mutation in their peripheral blood leukocyte DNA. Haplotype analyses suggested that this case arose as a de novo occurrence of autosomal dominant DEB. These cases illustrate the consequences of COL7A1 glycine substitution mutations underlying DEB in terms of the mode of inheritance and the phenotype, with profound implications for genetic counseling of individuals at risk for recurrence of DEB in subsequent offspring or future generations.

A study of the steroid sulfatase gene in families with X-linked ichthyosis using polymerase chain reaction

We have studied the steroid sulfatase (STS) gene in three Japanese families with X-linked ichthyosis (XLI), using polymerase chain reaction (PCR). PCR was performed using three sets of intraexonic primers covering exons 1, 5 and 10. In affected individuals from two of the families, DNA was not amplified in any of the three exons, suggesting that XLI in these families was due to the complete deletion of the STS gene. In affected individuals in the remaining family, DNA was amplified in predicted sizes in exons 1 and 5, but not in exon 10, suggesting that XLI in this family was due to partial deletion of the STS gene including exon 10. These results suggested that STS gene deficiency is heterogeneous in Japanese families with XLI. PCR is useful for the rapid diagnosis of XLI, the differentiation of XLI from ichthyosis vulgaris, and genetic counseling of XLI families. The PCR method was not applicable for carrier detection.

Type VII collagen DNA linkage analysis in a Japanese family with dominant dystrophic epidermolysis bullosa

Type VII collagen, a major component of anchoring fibrils in the basement membrane zone, is now considered to be a primary genetic factor in the pathogenesis of dominant dystrophic epidermolysis bullosa (DDEB). In this study, we performed genetic linkage analysis in a Japanese family with DDEB using a PvuII polymorphism in the type VII collagen gene. The pedigree consisted of 10 affected and 13 unaffected living individuals and was diagnosed as having Cockayne-Touraine type of DDEB. Electron microscopic examination of the skin demonstrated a diminished number and rudimentary structure of anchoring fibrils. PCR-based detection of PvuII polymorphism resulted in 3 genotypes and co-segregated with DDEB phenotype in this pedigree. The maximum lod score was 2.10 at recombination fraction (theta) of 0. The absence of recombination between DDEB and type VII collagen gene locus, as well as the observation of altered anchoring fibrils, suggested that type VII collagen is a candidate gene for the Japanese family with DDEB, although the lod score was statistically not significant.

Mouse 230-kDa bullous pemphigoid antigen gene: structural and functional characterization of the 5'-flanking region and interspecies conservation of the deduced amino-terminal peptide sequence of the protein

The 230-kDa bullous pemphigoid antigen is a hemidesmosomal protein of the cutaneous basement membrane zone. The primary sequences deduced from full-length human cDNAs predict that this molecule consists of a central rod region and flanking globular domains. To get insight into regulation of the 230-kDa bullous pemphigoid antigen gene (BPAG1), and to evaluate evolutionary conservation of the amino-terminus of the protein, we screened a mouse genomic DNA library with a 0.3-kb cDNA corresponding to the 5' end of the human 230-kDa bullous pemphigoid antigen cDNA. A positive clone was isolated, and Southern analysis of the clone with the 0.3-kb cDNA allowed isolation of a 3.0-kb Hind III fragment containing the 5' end of the coding sequence. Alignment of the sequences of this subclone and human BPAG1 sequences revealed that this fragment contained 2466 bp of 5'-flanking DNA, upstream from the ATG translation initiation site, and 258 bp of translatable sequences that encode a putative polypeptide of 86 amino acids at the amino-terminus of the protein. This deduced polypeptide showed 91% homology with the corresponding human sequence. The TATAAA and CCAAT consensus sequences, as well as several putative cis-regulatory elements, were identified in the 5'-flanking region of the mouse DNA. To test the functional promoter activity of the 5'-flanking DNA, three mouse BPAG1 promoter/CAT reporter gene constructs, with the promoter segments spanning from -1133, -525, and -213 to -1, were developed. Transient transfections of mouse transformed keratinocytes (Pam 212 cells) with these constructs revealed clearly detectable CAT activities, indicating that the 5'-flanking region contains a functional promoter. Furthermore, these experiments suggested that the upstream sequences contain upregulatory elements, as well as elements that confer, at least in part, tissue specificity to the expression of the mouse 230-kDa BPA gene.

Proteinase-resistant prion protein accumulation in Syrian hamster brain correlates with regional pathology and scrapie infectivity

Multiple lines of evidence indicate that PrPSc, found only in scrapie, is a necessary component of the infectious scrapie agent. Equally compelling is the evidence that its accumulation in the brain causes the neuropathology characteristic of scrapie. We measured the regional concentration of PrPSc in nine brain regions throughout the course of scrapie in the Syrian hamster following intrathalamic inoculation of prions. PrPSc was compared to the regional concentration of glial fibrillary acidic protein, a measure of reactive astrocytic gliosis. PrPSc was detected first in the thalamus 14 to 21 days postinoculation and next in the septum at 28 days. Initiation of PrPSc synthesis and accumulation in the thalamus was attributable to the inoculum and in the septum to ventricular spread of de novo synthesized PrPSc. The timing and pattern of PrPSc accumulation in all other brain regions suggested transmission along neuroanatomic pathways. Reactive astrocytic gliosis followed PrPSc accumulation in each region by 1 to 2 weeks. Brain PrPSc, determined by summing the concentrations in each brain region, correlated well with scrapie infectivity titers throughout the course of infection (correlation coefficient = 0.975; slope of linear regression line = 1.136). Our results support the hypothesis that PrPSc participates in both the etiology and pathogenesis of prion diseases.

Application of 2-aminopyridine fluorescence labeling to glycosaminoglycans

A pyridylamination method was applied to glycosaminoglycans and the characteristics of the resulting pyridylamino glycosaminoglycans were examined. First, glycosaminoglycan chains, which uniformly possess a xylose residue at their reducing termini, were liberated from proteoglycan by successive digestion with protease and endo-beta-xylosidase. Then the glycosaminoglycan chains were coupled with 2-aminopyridine by reductive amination with sodium cyanoborohydride for 15 h according to the method of Hase, S. et al. [J. Biochem. 95, 197-203 (1984)]. The pyridylamination reaction caused neither depolymerization, de-N-acetylation, nor de-N- or de-O-sulfation. The pyridylamino glycosaminoglycan chains had an intact linkage region (GlcA-Gal-Gal-Xyl) between the carbohydrate chain and the peptide core of the proteoglycan. These pyridylamino glycosaminoglycans should be useful as substrates for endo-type glycosidases that act on glycosaminoglycan chains and as markers for studies of glycosaminoglycan metabolism.

Characterization of beta-D-xyloside-induced glycosaminoglycans and oligosaccharides in cultured human skin fibroblasts

Human skin fibroblasts were incubated in the presence of a fluorogenic xyloside, 4-methylumbelliferyl beta-D-xyloside. Three fluorogenic components were isolated and purified from the culture medium by gel permeation high-performance liquid chromatography. Their structures were then characterized by enzymatic digestion, fast-atom-bombardment mass spectrometry, gas-liquid chromatography, and electrophoresis on cellulose acetate membrane. The results showed that one of the components was a mixture of dermatan sulfate (70%) and chondroitin sulfate (30%), bearing the 4-methylumbelliferone at the reducing termini, and having an average molecular weight of 9,200. The others had the structures galactosyl-galactosyl-xylosyl-4-methylumbelliferone and galactosyl-xylosyl-4-methylumbelliferone, respectively, representing the linkage region between the glycosaminoglycan chains and core protein, except that 4-methylumbelliferone replaced the amino acid. Moreover, it was demonstrated that these oligosaccharides were intermediates of glycosaminoglycan synthesis, not depolymerized products.

Determination of the reducing terminal sugars of glycosaminoglycans using 2-aminopyridine

The fluorescence labeling method (Takemoto, H. et al. (1985) Anal. Biochem. 145, 245-250) has been shown to have high sensitivity for measuring the sugar composition of glycoproteins. In the present study, its applicability for analysis of the reducing terminal sugars of glycosaminoglycans was investigated. The procedure involved coupling of glycosaminoglycans with 2-aminopyridine, followed by hydrolysis and N-acetylation, and then analysis by high-performance liquid chromatography on a reverse-phase column. The method was found to be useful for simultaneous determination of acidic, neutral and amino sugars at the reducing termini of glycosaminoglycan moieties.

Presence of an endo-beta-galactosidase degrading the linkage region between the chondroitin sulfate chain and core peptide of proteoglycan

Pyridylamino chondroitin sulfate, of which the reducing terminal xylose was coupled with a fluorescent 2-aminopyridine, was incubated at pH 4.0 with an extract from the mid-gut gland of Patnopecten. The high- and low-molecular-weight products were separated by ethanol precipitation, and identified by high-performance liquid chromatography analysis. The enzyme was found to expose a galactose residue at the reducing terminus of chondroitin sulfate, and also released the pyridylamino disaccharide, galactosylxylose, from the reducing terminal site of pyridylamino chondroitin sulfate. These results suggest that endo-beta-galactosidase activity, which hydrolyzes the galactosylgalactose linkage of peptidochondroitin sulfate, is present in the mid-gut gland of Patnopecten.

Isolation and characterization of Patnopecten mid-gut gland endo-beta-xylosidase active on peptidochondroitin sulfate

An endo-beta-xylosidase acting on the linkage region of peptidochondroitin sulfate was isolated from the mid-gut gland of the mollusc Patnopecten and purified about 375-fold, using a combination of ammonium sulfate fractionation, gel filtration on Sephacryl S-200, and DEAE-Sephacel chromatography. The pH optimum and the isoelectric point of this enzyme were 4.0 and 7.0, respectively. The molecular weight, estimated by gel filtration through Sephacryl S-200, was 78,000. The purified enzyme was completely free from protease, exoglycosidases, sulfatase, and phosphatase. This enzyme hydrolyzed the xylosyl serine linkage of the linkage region of various glycosaminoglycans, that is chondroitin sulfate, dermatan sulfate and heparan sulfate, all possessing a very small peptide segment, but not proteoglycans. It was concluded that this endo-beta-xylosidase was involved in the catabolism of proteoglycans.

Preparation and application of a fluorogenic substrate for endo-beta-xylosidase

The present paper describes a fluorometric assay for galactosaminoglycan-degrading endo-beta-xylosidase, utilizing glycosaminoglycan chains bearing a 4-methylumbelliferyl group at the reducing terminus as a substrate. This fluorogenic substrate is synthesized by human skin fibroblasts cultured in the presence of a fluorogenic xyloside, 4-methylumbelliferyl-beta-D-xyloside. The assay is based on measurement of the fluorescence of 4-methylumbelliferone, enzymatically liberated from the synthetic substrate by endo-beta-xylosidase. We examined the applicability of the assay for analysis of endo-beta-xylosidase activity.