447 research outputs found

    Comparative genomic analysis of the zebra finch degradome provides new insights into evolution of proteases in birds and mammals

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    <p>Abstract</p> <p>Background</p> <p>The degradome -the complete repertoire of proteases in an organism- is involved in multiple key biological and pathological processes. Previous studies in several organisms have yielded sets of curated protease sequences which may be used to characterize the degradome in a novel genome by similarity. Differences between degradomes can then be related to physiological traits of the species under study. Therefore, the sequencing of the zebra finch genome allows the comparison between the degradomes of mammals and birds and may help to understand the biological peculiarities of the zebra finch.</p> <p>Results</p> <p>A set of curated protease sequences from humans and chicken was used to predict the sequences of 460 protease and protease-like genes in the zebra finch genome. This analysis revealed important differences in the evolution of mammalian and bird degradomes, including genomic expansions and deletions of caspases, cytotoxic proteases, kallikreins, matrix metalloproteases, and trypsin-like proteases. Furthermore, we found several zebra finch-specific features, such as duplications in <it>CASP3 </it>and <it>BACE</it>, and a large genomic expansion of acrosin.</p> <p>Conclusions</p> <p>We have compared the degradomes of zebra finch, chicken and several mammalian species, with the finding of multiple differences which illustrate the evolution of the protease complement of these organisms. Detailed analysis of these changes in zebra finch proteases has shown that they are mainly related to immunological, developmental, reproductive and neural functions.</p

    Molecular cloning and expression of collagenase-3, a novel human matrix metalloproteinase produced by breast carcinomas

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    Esta publicación detalla los experimentos realizados para la clonación de un ADNc que codifica una nueva metaloproteasa de matriz extracelular a partir de una biblioteca de ADNc procedente de un carcinoma mamario. Este trabajo es de gran interés en la investigación del cáncer, ya que describe la identificación de una nueva colagenasa en los carcinomas mamarios proponiendo un posible papel en el proceso tumoral. Hay evidencia de que las metaloproteasas participan en el proceso de degradación proteolítica de los diferentes componentes de la membrana basal, favoreciendo así la invasión tumoral y las metástasis. El ADNc de la colagenasa-3 se expresó en un sistema de virus vaccinia, y la proteína recombinante fue capaz de degradar los colágenos fibrilares, lo que apoya la hipótesis de que el ADNc aislado codifica para una colagenasa auténtica. El análisis por Northern blot del ARN de tejidos normales y patológicos demostró la existencia de tres especies diferentes de ARNm en los tumores de mama, que parecen ser el resultado de la utilización de distintos sitios de poliadenilación presentes en la región 3'-no codificante del gen. Por el contrario, no se detectó ARNm de la colalagenasa-3 por Northern blot ni por PCR en otros tejidos humanos como mama normal, fibroadenomas mamarios, hígado, placenta, ovario, útero, próstata y glándula parótida. Sobre la base del aumento de la expresión de la colagenasa-3 en los carcinomas de mama y la ausencia de expresión detectable en los tejidos normales, se propone un posible papel de esta metaloproteinasa en el proceso tumoral

    Loss of genes implicated in gastric function during platypus evolution

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    Several genes implicated in food digestion have been deleted or inactivated in platypus. This loss perhaps explains the anatomical and physiological differences in the gastrointestinal tract between monotremes and other vertebrates and provides insights into platypus genome evolution

    Substrate Profiling of Tobacco Etch Virus Protease Using a Novel Fluorescence-Assisted Whole-Cell Assay

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    Site-specific proteolysis of proteins plays an important role in many cellular functions and is often key to the virulence of infectious organisms. Efficient methods for characterization of proteases and their substrates will therefore help us understand these fundamental processes and thereby hopefully point towards new therapeutic strategies. Here, a novel whole-cell in vivo method was used to investigate the substrate preference of the sequence specific tobacco etch virus protease (TEVp). The assay, which utilizes protease-mediated intracellular rescue of genetically encoded short-lived fluorescent substrate reporters to enhance the fluorescence of the entire cell, allowed subtle differences in the processing efficiency of closely related substrate peptides to be detected. Quantitative screening of large combinatorial substrate libraries, through flow cytometry analysis and cell sorting, enabled identification of optimal substrates for TEVp. The peptide, ENLYFQG, identical to the protease's natural substrate peptide, emerged as a strong consensus cleavage sequence, and position P3 (tyrosine, Y) and P1 (glutamine, Q) within the substrate peptide were confirmed as being the most important specificity determinants. In position P1′, glycine (G), serine (S), cysteine (C), alanine (A) and arginine (R) were among the most prevalent residues observed, all known to generate functional TEVp substrates and largely in line with other published studies stating that there is a strong preference for short aliphatic residues in this position. Interestingly, given the complex hydrogen-bonding network that the P6 glutamate (E) is engaged in within the substrate-enzyme complex, an unexpectedly relaxed residue preference was revealed for this position, which has not been reported earlier. Thus, in the light of our results, we believe that our assay, besides enabling protease substrate profiling, also may serve as a highly competitive platform for directed evolution of proteases and their substrates
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