This is the first report to demonstrate that canine atopic dermatitis is associated with over-production of IL-4. Clinical tolerance in healthy individuals appears to be associated with TGF-beta, although it is unclear if this reflects an active mechanism or simply non-responsiveness of the immune system. Th1 cytokines may be induced by subsequent self-trauma and secondary infections in atopic skin. We believe that these results better characterize spontaneously occurring canine atopic dermatitis. We further propose that this should be investigated as a possible animal model of human atopic dermatitis.

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The complete amino acid sequence (433 residues) of the human neurone-specific y isozyme of enolase (NSE) has been determined by a combination of direct amino acid sequencing and nucleotide sequencing of cloned cDNA. Substantial amino acid sequence of the non-neuronal a form of the enzyme was also obtained which agreed almost entirely with the indirect cDNA sequence [9]. Comparison of the two human sequences shows no insertions or deletions, but 72 replacements. Comparison of the human y form with the corresponding isozyme from the rat shows only 7 replacements (compared to 27 changes between the human and rat a isozymes). We have identified regions of sequence difference between the human c( and y forms that are mainly hydrophilic in character (residues 271 -285,298-316 and 416-433). These residues are on the surface of the three-dimensional structure [21] and could be useful as immunogens to produce antibodies specific for the neurone-specific form.The glycolytic enzyme enolase (2-phospho-~-glycerate hydrolyase), which catalyses the interconversion of 2-phosphoglycerate and phosphoenolpyruvate, occurs in three homologous but distinct isozymic forms a, fl and y [l, 21. The active enzyme is a dimer of non-covalently linked subunits ( M , 47000) that can also form heterodimers [3]. The a and B subunits are found in many tissues, the p subunit being predominant in muscle, whereas the enzyme from brain contains either a or y subunits. The y form is found only in neurones and neuroendocrine tissue; this has led to the y form being designated as neurone-specific enolase (NSE) and the a form as non-neuronal enolase (NNE). Considerable interest has focussed upon the tissue specificity of enolase, and on the control of its expression. The y isozyme is of medical interest because it is found in elevated concentrations in the plasma of patients suffering from tumors with neuroendocrine features such as neuroblastoma [4] or small-cell carcinoma of the lung [5]. Comparative structural studies can reveal potential epitopes that could facilitate the production of monoclonal antibodies able to distinguish the y form specifically which could have useful application as analytical and diagnostic reagents.The amino acid sequences of the a and y forms of the rat isozymes have been determined by cDNA sequencing [6 -81, as has that of the human a isozyme [9]. Direct amino acid sequencing gave the sequence of the chicken muscle fl isozyme[lo] which is one of the forms together with the yeast 1 form [I 1,221 that have given crystals suitable for X-ray crystallography. Two yeast isozymes [ 121 and a non-neuronal-like enolase from Xenopus luevis [13] techniques. We report here the results of amino acid and cDNA sequencing of the human y isozyme which together have determined the complete sequence of this isozyme. Comparison with the sequence of the CI isozyme has allowed us to identify regions of potential immunogenic difference which may help in the production of antibodies capable of discriminating between these two human isozymes. M...

No abstract

Cofactor-independent phosphoglyceromutase (PGM) was purified to homogeneity from developing castor seed endosperm. Immunological characterization using monospecific antisera raised against this protein indicates that the enzyme is located in the cytosol and that there is no immunologically related polypeptide in the leucoplast from this tissue. Isolation and sequence determination of full-length cDNA clones for castor and tobacco PGM demonstrate that the protein is highly conserved in these plants and is closely related to the maize enzyme. A comparison of the amino acid sequence of peptides derived from Neurospora crassa PGM with the cofactor-independent enzyme from higher plants demonstrated that they are related and may have diverged from a common ancestral gene. The previously proposed relationship between higher-plant PGM and alkaline phosphatases is not supported by sequence analysis of the castor and tobacco enzymes. Expression of the single castor cytosolic PGM gene correlates well with other cytosolic glycolytic genes in developing and germinating castor seeds, and with the appearance of enzyme activity and PGM polypeptides in these tissues.

The gene encoding the malarial homologue of proliferating cell nuclear antigen, PCNA, has been identified and characterised. It is located on chromosome 13. The coding sequence of 825 nucleotides predicts a protein of 30,586 Da. There are no introns and northern analysis reveals a transcript of approximately 1.6kb. The conserved residues which characterise the PCNAs of human, Drosophila, Saccharomyces and Xenopus are present in PfPCNA but the overall identity of PfPCNA with human and yeast PCNAs is low; 34% and 31% respectively. PfPCNA is longer than the PCNAs of these other species by about 16 amino acids, most of which are present in a block near the carboxy terminus. Antibodies against a purified PfPCNA-glutathione-S-transferase fusion protein recognise a single band in western blots of parasite extracts at 32kDa. The same antiserum has been used to demonstrate that the expression of PfPCNA is regulated during the intraerythrocytic development of the parasite. Expression increases dramatically in late trophozoites and is maintained during the subsequent nuclear divisions which produce schizonts.

Genes encoding proteins homologous to the catalytic subunits of DNA polymerase alpha and delta have been cloned from the human malaria parasite Plasmodium falciparum. These are among the first cellular replicative DNA polymerase genes to be cloned and their sequences allow us to make new statements about the relative degrees of conservation of these two enzymes. The most important finding was that P. falciparum Pol delta showed considerable homology to the only other Pol delta enzyme for which published sequence is available, that of S. cerevisiae, displaying an overall amino acid identity of 45% and identity over a highly conserved central region of 59%. In contrast, the level of identity shown over the equivalent central region of Pol alpha between the P. falciparum and S. cerevisiae sequences is only 32%. The sequence data also allowed us to examine the degree of conservation in putative exonuclease domains of Pol delta. The Pol delta gene of P. falciparum maps to chromosome 10 and evidence is presented for the presence of different sized Pol delta mRNA's in the asexual and sexual erythrocytic stages of parasite development.

The gene encoding DNA polymerase alpha from the human malaria parasite Plasmodium falciparum has been sequenced and characterised. The deduced amino acid sequence possesses the seven sequence motifs which characterise eukaryotic replicative DNA polymerases (I-VII) and four of five motifs (A-E) identified in alpha DNA polymerases. The predicted protein also contains sequences which are reminiscent of Plasmodium proteins but absent from other DNA polymerases. These include four blocks of additional amino acids interspersed with the conserved motifs of the DNA polymerases, four asparagine rich sequences and a novel carboxy-terminal extension. Repetitive sequences similar to those found in other malarial proteins are also present. cDNA-directed PCR was used to establish the presence of these features in the approximately 7kb mRNA. The coding sequence contains a single intron. The gene for DNAPol alpha is located on chromosome 4 and is transcribed in both asexual and sexual erythrocytic stages of the parasite.