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The Challenge of Parasite Control
Published in Eric S. Loker, Bruce V. Hofkin, Parasitology, 2023
Eric S. Loker, Bruce V. Hofkin
Transgenesis refers to the deliberate introduction of exogenous genetic material into a living organism. The newly acquired genes, called transgenes, endow the recipient organism with new properties that will be transmitted to progeny. Such genetic engineering has increasingly been considered as a means of vector control. If vector capacity can be reduced with this technique, the hope is that transgenic vectors can be released into areas of endemicity, resulting in reduced transmission and morbidity. Such genetic methods, usually used in tandem with more conventional control, have been under investigation since the 1950s. The operational application of genetically altered vectors to reduce transmission has proven to be one of the most difficult challenges of vector control. Nevertheless, over the last two decades, there have been tremendous advances in the fields of vector genomics and proteomics and in the ability to genetically manipulate medically relevant vectors. Consequently, encouraging results in the laboratory are beginning to show promise in the field, and in some cases, the use of transgenic vectors to control disease transmission is already operational.
Hair Follicle Keratins
Published in John P. Sundberg, Handbook of Mouse Mutations with Skin and Hair Abnormalities, 2020
George E. Rogers, Barry C. Powell
The current phase of the characterization of keratin genes is being overtaken by studies focused on regulation of expression of members of the keratin complex, which are synthesized at a specific time and cellular location during hair growth. In relation to this, analysis in our laboratory of the flanking promoter regions of their genes has revealed several oligonucleotide sequences as potential control elements, and two test systems are being used to investigate them. One is mouse transgenesis, in which the specificity and efficiency of mutated promoter regions driving a reporter gene are compared with the expression of the endogenous gene. The other approach is to examine follicle extracts for proteins (potential transcription factors) that specifically bind to selected regions of the promoter sequence in in vitro DNA mobility assays.
Animal Models of Down Syndrome and Other Genetic Diseases Associated with Mental Retardation
Published in Merlin G. Butler, F. John Meaney, Genetics of Developmental Disabilities, 2019
Angela J. Villar, Charles J. Epstein
There are some serious limitations inherent in the approaches directed at dissecting individual gene function. The random site of integration and the variability of copy number can affect the quantitative expression of the transgene. Other concerns are the possible disruption of an endogenous gene by a transgenic insertion event, which can result in a mutant phenotype as a consequence of a disruption, deletion, or translocation, rather than as a consequenceof transgenesis. Finally, whereas genes under control of their natural promoters are expected to recapitulate the cell-type- and stage-specific expression of the endogenous genes, reflecting the genetic situation in DS, the use of heterologous promoters that may allow the generation of inducible transgenic models can lead to nonphysiological effects. Therefore, the best way to produce a transgenic mouse is to introduce the gene under the transcriptional control of its own promoter. In addition, when selecting a candidate gene for the making of a transgenic mouse, knowledge of the functions of the protein that the transgene encodes and of its spatiotemporal pattern of expression should be considered.
How necessary are animal models for modern drug discovery?
Published in Expert Opinion on Drug Discovery, 2021
Transgenic animals have a foreign gene introduced into their genome. Such animals are usually produced by DNA microinjection into the pronuclei of a fertilized egg that is subsequently implanted into the oviduct of the surrogate mother. Transgenic animals have become a key tool in functional genomics in order to generate models for human diseases and validate new drugs [20]. Transgenesis includes the addition of foreign genetic information to animals and specific inhibition of endogenous gene expression. The knockout animals are transgenic that have a specific interest gene disabled are transgenic, and are widely used to investigate both normal gene function, as well as the analyses of patho-biological roles of select genes involved in various disease states [21]. In addition, such transgene/knockout animal models are actively used in the development of new therapeutics and associated strategies.
The Drosophila foraging gene plays a vital role at the start of metamorphosis for subsequent adult emergence
Published in Journal of Neurogenetics, 2021
Ina Anreiter, Aaron M. Allen, Oscar E. Vasquez, Lydia To, Scott J. Douglas, Javier V. Alvarez, John Ewer, Marla B. Sokolowski
The galK selection/counter-selection (as in Warming, Costantino, Court, Jenkins, & Copeland, 2005) was used to introduce a premature stop codon and transcription terminator into a bacterial artificial chromosome (BAC) containing the 35 kb for locus. Generation of this 35 kb construct was previously described (Allen et al., 2017). The GalK sequence was PCR amplified with comStop-galK-F and comStop-galK-R primers (Table S1) and integrated into the BAC at the start of the first coding exon common to all transcripts. An hsp70 transcription terminator was amplified with primers comStop-F and comStop-R (Table S1). A single SNP was included in the for specific region of the comStop-F to introduce a premature stop codon once integrated into the locus (Y573X, relative to for-PA). This PCR product was then used to replace the GalK sequence in the for BAC, introducing a premature stop codon and transcription terminator. The BAC was verified by PCR, restriction digest, and Sanger sequencing. The BAC was incorporated into the fly’s genome using φC31 integration into the attP2 landing site on the third chromosome (Groth, Fish, Nusse, & Calos, 2004). Transgenesis was performed by Genetic Services Inc.
Expression of the foraging gene in adult Drosophila melanogaster
Published in Journal of Neurogenetics, 2021
Aaron M. Allen, Marla B. Sokolowski
The KpnI–NotI fragment from the pSC-LHA-IRES-dmGAl4-FRT-kan-FRT-RHA vector was transformed into EL250 E. coli strain (Lee et al., 2001) which already contained a bacterial artificial chromosome (BAC) containing the 35 kb foraging locus (previously described in Allen et al., 2017). Recombineered BACs were selected by kanamycin resistance. The FRT-kan-FRT was then removed by arabinose induction. Proper integration Gal4 sequence and replacement of the foraging common coding region was verified with PCR, restriction digest, and Sanger sequencing. φC31 integration was used to integrate the BAC into the VK00013 landing site on the third chromosome (Venken, He, Hoskins, & Bellen, 2006). Transgenesis was performed by BestGene Inc. Primer design, in-slico cloning, and analysis of Sanger sequencing reactions were all performed in the Geneious 8 software package (Kearse et al., 2012).