Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.10.3.1 (tyrosinase)
 9,065 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

It is proposed that the phenol oxidase enzyme of schistosomes and other trematodes has a crucial role in the cross-linking of precursor proteins in the formation of the eggshell. However, to date there is no direct evidence to show that the enzyme catalyzes the reactions necessary for the posttranslational modification of eggshell precursor proteins. In this report we demonstrate that an eggshell precursor protein acts as a substrate for a schistosome fraction that catalyzed the 2 steps in the oxidation of tyrosine. This action of the phenol oxidase-containing worm fraction resulted in the tyrosine-dependent insolubilization and aggregation of the protein, suggesting a role for the enzyme in the posttranslational modification and cross-linking of schistosome eggshell proteins. The enzyme-rich fraction from Schistosoma mansoni catalyzed both steps of the reactions necessary for the conversion of tyrosine residues on putative eggshell precursor protein (p48) to quinones. The parasite fraction also catalyzed the hydroxylation of free L-tyrosine to DOPA (monophenol oxidase activity) and the oxidation of L-DOPA to dopaquinone (diphenol oxidase activity). Both activities of the enzyme are avidly bound to membranous structures, are susceptible to agents known to inhibit a functionally related enzyme, tyrosinase, and may reside on the same protein.
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PMID:Characteristics of phenol oxidase of Schistosoma mansoni and its functional implications in eggshell synthesis. 850 88

For the emerging amphibian genetic model Xenopus tropicalis targeted gene disruption is dependent on zinc-finger nucleases (ZFNs) or transcription activator-like effector nucleases (TALENs), which require either complex design and selection or laborious construction. Thus, easy and efficient genome editing tools are still highly desirable for this species. Here, we report that RNA-guided Cas9 nuclease resulted in precise targeted gene disruption in all ten X. tropicalis genes that we analyzed, with efficiencies above 45% and readily up to 100%. Systematic point mutation analyses in two loci revealed that perfect matches between the spacer and the protospacer sequences proximal to the protospacer adjacent motif (PAM) were essential for Cas9 to cleave the target sites in the X. tropicalis genome. Further study showed that the Cas9 system could serve as an efficient tool for multiplexed genome engineering in Xenopus embryos. Analysis of the disruption of two genes, ptf1a/p48 and tyrosinase, indicated that Cas9-mediated gene targeting can facilitate direct phenotypic assessment in X. tropicalis embryos. Finally, five founder frogs from targeting of either elastase-T1, elastase-T2 or tyrosinase showed highly efficient transmission of targeted mutations into F1 embryos. Together, our data demonstrate that the Cas9 system is an easy, efficient and reliable tool for multiplex genome editing in X. tropicalis.
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PMID:Efficient RNA/Cas9-mediated genome editing in Xenopus tropicalis. 2440 72