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Important Information to Consider Before Ordering Clones

Please note that the CMHD gene trap resource is a part of the WL Stanford academic laboratory at the University of Toronto focusing on generating animal models for human disease; analyzing and manipulating stem cell biology utilizing genetic, biochemical and nanotechnological approaches; and developing new regenerative medicine therapeutics.The parental ES cells, but not individual clone lines, are routinely tested and found to be mycoplamsa negative. A very high percentage of ES cell lines, but not all, yield germline-transmitting chimeras.

Gene trap ES cell lines are NOT knockouts. These random insertions are often mutagenic, even leading to null mutations. However, the insertion site in a clone is a critical determinant of the type of mutation generated. Insertions occurring in the 5' coding region will likely generate a null mutation, while other types of insertions lead to hypomorphic or neomorphic mutations, even dominant negative mutations. This is dependent upon the gene structure and function as well as the type of gene trap vector used. The CMHD gene trap resource is part of the International Gene Trap Consortium, IGTC. The CMHD gene trap resource complements the other IGTC resources by providing a library of polyA trap clones. We have found that polyA vectors are able to trap a substantially greater fraction of the genome than other vectors. Alas, we have also discovered that polyA insertions, often occur in the 3' end of genes. This occurs because most insertions in the 5' exons activate non-sense mediated decay (NMD), leading to an inability to select for 5' insertions. Since then we have developed novel vectors to overcome and utilize NMD to target the trapped gene for degradation. We also have a complement of gene trap vectors in which the polyA site of beta galactosidase reporter was deleted. This will result in an unstable trapped transcript, leading to hypomorphic mutations but are unlikely to generate null mutations.

Before ordering your clones, we strongly recommend that you review the RACE trace file and blast the gene trap sequence tag against the USCS genome browser and/or NCBI mouse genome to make sure that the sequence tag maps to your gene of interest and that it is in the sense orientation with the gene. It is also important to review the vector information to make the best choice of the clones.

  • Once you have reviewed the above information and would like to proceed with the ordering process, go to ES Cell Clone Request.

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