Suman Virdee – Developing a Galaxy based Pipeline for RNA-Seq Analysis in Stem Cell Biology
Kirill Pankov – The Cytochrome P450 (CYP) Superfamily in the Cnidarian Phylum
Jonsson Liu – Clinical virulence detection and Clostridium difficile clonality
Annie Cheng – Predicting Plasmid-Mediated Antimicrobial Resistance from Whole Genome Sequencing
Godwin Chan – Using the Galaxy Platform to Increase Accessibility for Structure Determination via Cryo-Electron Microscopy
Three of our undergraduate students gave poster presentations in the last month. Arjun Sharma (Biochemistry & Biomedical Sciences 3rd year) outlined his work on developing the Comprehensive Antibiotic Resistance Database’s (arpcard.mcmaster.ca) CARD*Shark text mining algorithms at the Michael G. DeGroote Institute for Infectious Disease Research (IIDR) Trainee Day while Kirill Pankov (Biomedical Discovery & Commercialization 4th year) presented the results of his summer NSERC Undergraduate Student Research Award (USRA) research in the Laboratory of Dr. Joanna Wilson into the origin of Cnidarian P450 enzymes, work he is continuing in our lab as part of his thesis research. Mohammad Khan (Biomedical Discovery & Commercialization 4th year), a thesis student in the Laboratory of Dr. Eric Brown that collaborates with our group, also presented a poster at IIDR Trainee Day on his work on chemical-genetic interaction database design.
Sharma, A.N., S. Doshi, A.R. Raphenya, B. Alcock, B.M. Dave, B.A. Lago, K.K. Tsang, & A.G. McArthur. 2016. CARDShark: Computer-assisted biocuration of the Comprehensive Antibiotic Resistance Database. Poster presentation at the 2016 Michael G. DeGroote Institute for Infectious Disease Research (IIDR) Trainee Day, Hamilton, Ontario, Canada.
Pankov, K., A.G. McArthur & J.Y. Wilson. 2016. The Cytochrome P450 (CYP) superfamily in the Cnidarian phylum. Poster presentation at the 2016 Undergraduate Student Research Awards (USRA) Poster Session, Hamilton, Ontario, Canada.
Khan, M.A., S. French, B. Aubie, A.G McArthur & E.D. Brown. 2016. Challenging common screening filters through analysis of a chemical-genetic screening database. Poster presentation at the 2016 Michael G. DeGroote Institute for Infectious Disease Research (IIDR) Trainee Day, Hamilton, Ontario, Canada.
Cytochrome P450 (CYP) proteins compose a highly diverse superfamily found in all domains of life. These proteins are enzymes involved in metabolism of endogenous and exogenous compounds. In vertebrates, the CYP2 family is one of the largest, most diverse and plays an important role in mammalian drug metabolism. However, there are more than 20 vertebrate CYP2 subfamilies with uncertain evolution and fairly discrete subfamily composition within vertebrate classes, hindering extrapolation of knowledge across subfamilies. To better understand CYP2 diversity, a phylogenetic analysis of 196 CYP2 protein sequences from 16 species was performed using a maximum likelihood approach and Bayesian inference. The analyses included the CYP2 compliment from human, fugu, zebrafish, stickleback, medaka, cow, and dog genomes. Additional sequences were included from rabbit, marsupial, platypus, chicken, frog, and salmonid species. Three CYP2 sequences from the tunicate Ciona intestinalis were utilized as the outgroup. Results indicate a single ancestral vertebrate CYP2 gene and monophyly of all CYP2 subfamilies. Two subfamilies (CYP2R and CYP2U) pre-date vertebrate diversification, allowing direct comparison across vertebrate classes, while all other subfamilies originated during vertebrate diversification, often within specific vertebrate lineages. Analysis of site-specific evolution indicates that some substrate recognition sites (SRS) previously proposed for CYP genes do not have elevated rates of evolution, suggesting that these regions of the protein are not necessarily important in recognition of CYP2 substrates. Type II functional divergence analysis identified multiple residues in the active site of CYP2F, CYP2A, and CYP2B proteins that have undergone radical biochemical changes and may be functionally important.
Increasing use of zebrafish in drug discovery and mechanistic toxicology demands knowledge of cytochrome P450 (CYP) gene regulation and function. CYP enzymes catalyze oxidative transformation leading to activation or inactivation of many endogenous and exogenous chemicals, with consequences for normal physiology and disease processes. Many CYPs potentially have roles in developmental specification, and many chemicals that cause developmental abnormalities are substrates for CYPs. Here we identify and annotate the full suite of CYP genes in zebrafish, compare these to the human CYP gene complement, and determine the expression of CYP genes during normal development. Zebrafish have a total of 94 CYP genes, distributed among 18 gene families found also in mammals. There are 32 genes in CYP families 5 to 51, most of which are direct orthologs of human CYPs that are involved in endogenous functions including synthesis or inactivation of regulatory molecules. The high degree of sequence similarity suggests conservation of enzyme activities for these CYPs, confirmed in reports for some steroidogenic enzymes (e.g. CYP19, aromatase; CYP11A, P450scc; CYP17, steroid 17a-hydroxylase), and the CYP26 retinoic acid hydroxylases. Complexity is much greater in gene families 1, 2, and 3, which include CYPs prominent in metabolism of drugs and pollutants, as well as of endogenous substrates. There are orthologous relationships for some CYP1 s and some CYP3 s between zebrafish and human. In contrast, zebrafish have 47 CYP2 genes, compared to 16 in human, with only two (CYP2R1 and CYP2U1) recognized as orthologous based on sequence. Analysis of shared synteny identified CYP2 gene clusters evolutionarily related to mammalian CYP2 s, as well as unique clusters. Transcript profiling by microarray and quantitative PCR revealed that the majority of zebrafish CYP genes are expressed in embryos, with waves of expression of different sets of genes over the course of development. Transcripts of some CYP occur also in oocytes. The results provide a foundation for the use of zebrafish as a model in toxicological, pharmacological and chemical disease research.