Retrovirus-mediated gene transfer of transthyretin and transthyretin-methionine 30: a potential tool for the study of amyloidogenesis.

Familial amyloidotic polyneuropathy (FAP) is a genetic disease characterized by systemic amyloid deposition particularly in the peripheral nervous system. These deposits are composed mainly of a mutant form of the serum protein transthyretin (TTR) having a methionine for valine substitution at position 30-TTR Met 30. The factors involved in the formation of these deposits are unknown.

Structure of Met30 variant of transthyretin and its amyloidogenic implications.

Familial amyloidotic polyneuropathy (FAP) is an autosomal dominant hereditary type of lethal amyloidosis involving single (or double) amino acid substitutions in the amyloidogenic protein transthyretin (TTR). The most common type of FAP (Type I, or Portuguese) is characterized by a Val-->Met substitution at position 30. The Met30 variant of TTR has been produced by recombinant methods, crystallized in a form isomorphous with native TTR, subjected to X-ray analysis and compared structurally with the wild-type protein.

A Danish kindred with familial amyloid cardiomyopathy revisited: identification of a mutant transthyretin-methionine111 variant in serum from patients and carriers.

Purpose: In familial amyloid cardiomyopathy of Danish origin, the amyloid microfibrils contain a mutant transthyretin (TTR) with a methionine-for-leucine substitution at the molecular position 111. We studied the possible occurrence of this variant TTR-Met111 in serum from afflicted as well as nonafflicted family members and their offspring, in order to define its possible role as predictor of the disease and to describe its mode of inheritance.

Patients And Methods: Stored, frozen serum samples obtained from 1959 through 1960 from 36 of 40 living members of the kindred were analyzed.

Amyloidogenic and non-amyloidogenic transthyretin Asn 90 variants.

Recently, a new transthyretin (TTR) variant was described in the normal Portuguese and German populations. The same substitution was found associated with familial amyloidotic polyneuropathy (FAP) in an American family of Italian origin. Comparative isoelectric focusing studies showed a difference in the mobility pattern between the non-pathogenic and pathogenic variants.

A new transthyretin mutation associated with amyloid cardiomyopathy.

In transthyretin (TTR) a new mutation (TTR-Thr45) has been identified in a patient with familial amyloidosis characterized clinically by prominent cardiomyopathy and the absence of peripheral neuropathy. Comparative peptide mapping by high-performance liquid chromatography of the patient's plasma TTR together with normal TTR showed the presence of an abnormal tryptic peptide in the patient's TTR. The sequence of this peptide (peptide 6, residues 36-48) demonstrated the presence of a threonine-for-alanine substitution at position 45.

Arsenic-75 nuclear magnetic resonance: study of the interaction of arsenate with various molecules of biological interest.

75As NMR (Nuclear Magnetic Resonance) was used as a probe of arsenate interactions in solution. The linewidth at half-height of the 75As NMR signal of arsenate was studied as a function of solution pH and temperature. Below pH 11.

Specific removal of transthyretin from plasma of patients with familial amyloidotic polyneuropathy: optimization of an immunoadsorption procedure.

Familial amyloidotic polyneuropathy is characterized by the presence in patients plasma of a genetic variant of transthyretin. No specific treatment has been found and extracorporeal immunoadsorption on immobilized anti-transthyretin antibodies appears as a potentially attractive procedure. Parameters involved in specific immunoadsorption of transthyretin were studied and optimized.

Two transthyretin variants (TTR Ala-49 and TTR Gln-89) in two Sicilian kindreds with hereditary amyloidosis.

We report the biochemical and molecular characterization of two new transthyretin (TTR) variants in two Italian families with hereditary amyloidosis. Both families presented neuropathy and cardiomyopathy but they differ in other clinical features. These TTR variants were previously detected by isoelectric focusing (IEF); one is a neutral TTR variant and the other one is basic.

Transthyretin Leu 68 in a form of cardiac amyloidosis.

A form of transthyretin (TTR)-related cardiac amyloidosis was previously described in a German patient. Electrophoretic analysis of plasma TTR showed the presence of an electrically neutral variant. We have now characterized the variant transthyretin by comparative peptide mapping, aminoacid and DNA sequencing procedures.

Characterization of a basic transthyretin variant--TTR Arg 102--in the German population.

A basic transthyretin (TTR) variant, apparently non-pathogenic, has been reported in a German family. Protein analysis of this TTR variant revealed the substitution of arginine for proline at position 102 of the TTR polypeptide chain. This result was confirmed by DNA analysis of PCR amplified DNA.

Studies on the synthesis and secretion of transthyretin by the human hepatoma cell line Hep G2.

Transthyretin (TTR) is a circulatory protein which plays an important role in the transport of both thyroid hormone and retinol. Hep G2 cells, a human hepatoma-derived cell line, have been used extensively in studies of protein secretion by liver cells. The original description of this cell line indicated that this line, unlike primary hepatocytes, does not secrete TTR.

Anal tonometry: a quick method of anal manometry.

Evaluation of anal sphincter tonic activity is important in the proctologic clinic. However, manometric techniques are expensive, complex, and only available in some centers. Because there is often an in-office need for having objective measurements of anal tonic activity, in our clinic we introduced a simple method for measurement of anal pressures.

Molecular analyses of an acidic transthyretin Asn 90 variant.

A mutation in transthyretin (TTR Asn 90) has been identified in the Portuguese and German populations. This variant has a lower pI and was found by screening analyses in 2/4,000 German subjects and in 4/1,200 Portuguese by using either double one-dimensional (D1-D) electrophoresis with isoelectric focusing (IEF) or hybrid isoelectric focusing in immobilized pH gradient (HIEF) as the final separation step. The Portuguese population sample was from the area where TTR Met 30-associated familial amyloidotic polyneuropathy (FAP) prevails, and it was divided into (a) a group of 500 individuals belonging to FAP kindreds and (b) a group of 700 collected at random.

Production of recombinant human transthyretin with biological activities toward the understanding of the molecular basis of familial amyloidotic polyneuropathy (FAP).

Transthyretin (TTR) is a plasma protein interacting with thyroxine T4 and retinol binding protein (RBP). Several variants of TTR with single amino acid substitutions have been identified as the major components of the amyloid fibrils of familial amyloidotic polyneuropathy (FAP), a fetal, autosomal dominant genetic disease. The elucidation of the molecular nature of the variants distinct from that of the wild-type TTR is crucial for understanding the amyloidogenesis in FAP, but our understanding is very poor mainly because of the unavailability of pure variant TTRs.

Ocular changes in familial amyloidotic polyneuropathy with dense vitreous opacities.

Familial amyloid polyneuropathy (FAP) is a hereditary disease which eventually causes serious ocular problems. Seven eyes from patients with FAP 1 were vitrectomised, and the insoluble proteins from the vitreous were purified, the amyloid protein isolated, and the prealbumin characterised with a monoclonal antibody against amyloid fibril protein. Before surgery, visual acuity was very poor, due to abundant deposits in the vitreous, frequently attached to the posterior lens capsule.

Recent advances in the molecular pathology of familial amyloid polyneuropathy.

The familial amyloid polyneuropathies (FAP) represent a heterogeneous spectrum of clinical syndromes differing regarding age of onset, rate of progression, and distribution of organ involvement and affecting people from different ethnic groups. Several mutant forms of transthyretin (TTR, formerly referred to as prealbumin) have been identified both in circulating plasma and in amyloid deposits from FAP patients. It is possible that a common factor in the amyloidogenesis process exists among the different forms which might be related to a change produced by the mutation in the three-dimensional structure of TTR.

Cardiac amyloidosis: report of a patient heterozygous for the transthyretin isoleucine 122 variant.

Amyloid fibril material was extracted from autopsy material of a patient who died from progressive cardiac failure at age 64. He had enlarged heart on routine X-ray at age 47 and the first symptoms of cardiac failure at age 62. Fractionation of the fibril material resolved peptide fragments immunoreactive with anti-human transthyretin (TTR).

Prenatal diagnosis of familial amyloidotic polyneuropathy: evidence for an early expression of the associated transthyretin methionine 30.

Transthyretin methionine 30 (TTR Met 30), which is associated with familial amyloidotic polyneuropathy, originates in a single base substitution (A for G) in the second exon of the TTR gene. This autosomal dominant disease can be diagnosed by RFLP analysis of NsiI-digested DNA. The amplification of DNA by PCR improves the diagnosis method, making it suitable for prenatal diagnosis.

A new mutation causing familial amyloidotic polyneuropathy.

The DNA from an individual with familial amyloidotic polyneuropathy was examined. It did not possess any of the mutations which have previously been associated with familial amyloidotic polyneuropathy. However, a novel 7.

Tetramer formation of a variant type human transthyretin (prealbumin) produced by Escherichia coli expression system.

A variant of human transthyretin(TTR, prealbumin) with methionine for valine substitution at position 30 is a major component of amyloid fibrils found in patients of familial amyloidotic polyneuropathy(FAP) type I, an autosomal dominant genetic disease. But the molecular nature of the variant TTR has been obscure, because most of plasma TTR from FAP patients is a mixture of variant and wild type TTR and no pure preparation of the variant has been available. For this reason, we constructed a system in which the variant type TTR was efficiently synthesized.

Activity of a metallothionein-transthyretin fusion gene in transgenic mice. Possible effect of plasmid sequences on tissue-specific expression.

Three strains of transgenic mice carrying the mouse metallothionein-I (MT) promoter fused to the human transthyretin (TTR) structural gene plus pUC plasmid sequences were investigated for expression of the fusion gene. Human TTR was inducible in the serum of at least two strains and the fusion gene mRNA was detected in several tissues of all the strains. The testis showed constitutive mRNA synthesis, while the intestine and some other tissues showed inducible expression.

Simplified method for screening populations at risk for transthyretin Met30-associated familial amyloidotic polyneuropathy.

This simple, reliable method for detecting the transthyretin-methionine30 [TTR(Met30)] mutation, found in patients with familial amyloidotic polyneuropathy (FAP), is based on production of an extra peptide fragment when the mutant TTR is treated with cyanogen bromide (CNBr). After electrophoresis of whole serum and excision of the TTR (prealbumin) band, the TTR-containing gel is incubated with CNBr, subjected to sodium dodecyl sulfate/polyacrylamide gel electrophoresis, and stained with silver to determine whether an abnormal CNBr fragment (residues 31-127) is present. Results can be obtained within two days.

Haplotype analysis of familial amyloidotic polyneuropathy. Evidence for multiple origins of the Val----Met mutation most common to the disease.

Familial amyloidotic polyneuropathy (FAP) is an autosomal dominant genetic disease characterized by systemic accumulation of amyloid fibrils. A major component of FAP amyloid has been identified as variant transthyretin (TTR, also called prealbumin). In particular, a variant with the substitution 30Val----Met has been commonly found in FAP of various ethnic groups.

Familial amyloidotic polyneuropathy: transthyretin (prealbumin) variants in kindreds of Italian origin.

As part of an epidemiological study that aims to characterize chemically the mutation(s) in transthyretin (TTR) related to familial amyloidotic polyneuropathy (FAP) of different ethnic origins, studies were carried out on TTR from two FAP kindreds of Italian origin. Two different criteria were employed in the characterization of TTR from these kindreds: (1) immunoblotting of cyanogen bromide fragments for screening of TTR(Met30) and (2) isoelectric focusing. TTR(Met30) was not detected but other substitutions were demonstrated using isoelectric focusing techniques.