elegans heat shock promoter into the entomopathogenic nematode Heterorhabditis bacteriophora (87). Whilst the exogenous gene was extrachromosomal as suggested by the decreasing Dorsomorphin manufacturer percentage of reporter gene products detected in subsequent generations arising from the transformed parents, this was nevertheless a significant milestone in parasitic nematode transgenesis (Table 1). Since then, microinjection has been used to deliver exogenous genes into other parasitic nematodes including Strongyloides stercoralis. Here, gonadal microinjection was used to transfer
plasmid DNA encoding GFP under the control of two different S. stercoralis promoters into the developing embryos of free-living females (88). This technique for the introduction of exogenous genes had been well established in C. elegans two decades prior to its use in S. stercoralis (89,90), and structural similarities between the ovaries of free-living female Strongyloides spp. and C. elegans hermaphrodite ovaries enabled its adaptation of use in Strongyloides. The GFP reporter was observed predominantly in the maternal gonad, in intrauterine embryos and in embryonating eggs with an overall
transfection rate of approximately 3% of the progeny. Whilst none of the transformed embryos hatched, potentially because of the toxic accumulation of high GFP levels, these experiments provided the first strong evidence for the possibility of achieving heritable transformation, which up to then had not been achieved. Other methods EX 527 manufacturer for gene transfer have also been used successfully. A commonly utilized method of gene delivery is biolistic transformation, also known as particle bombardment. In the landmark article describing the www.selleck.co.jp/products/Paclitaxel(Taxol).html use of biolistics (11), embryos of Ascaris were successfully transformed with either a splice leader RNA (SL RNA) gene or a luciferase reporter gene driven by the SL RNA promoter sequence or alternative Ascaris-derived promoters. This study suggested the possibility
of utilizing different promoters and RNA processing elements for gene expression in nematodes. In addition to the transfection of DNA, this study also demonstrated the successful introduction of RNA into the parasite with expression detected as early as an hour after transfection. In another study, biolistics was successfully utilized to transform the filarial parasite, Litomosides sigmodontis (91). Here, GFP or β-galactosidase driven either by the C. elegans actin-1 core promoter or by the SV40 promoter was introduced into the parasite, and reporter activity was observed 2–10 days after transfection. Of note, a high degree of tissue-specific expression was achieved with β-galactosidase expression under the control of the actin-1 promoter.