Schistosomiasis is a serious global problem and the second most devastating parasitic disease following malaria. Currently, there is no effective vaccine available and treatment is entirely dependent on praziquantel chemotherapy, raising a significant threat to public health. The paucity of molecular tools to manipulate schistosome gene expression has made an understanding of genetic pathways in these parasites difficult, increasing the challenge of identifying new potential drug/vaccine candidates.
In this project we aim to establish a CRISPR (clustered regularly interspaced short palindromic repeat)-Case9-mediated gene knock-down system in Schistosoma japonicum. The CRISPR/Cas9 system allows cell genomes to be edited at targeted locations using the Streptococcus pyogenes Cas9 nuclease (SpCas9) under the guide of a single-guide RNA (sgRNA). Cas9-gRNAs targeting on gene-acetylcholinesterase (AChE) will be delivered into the schistosomule larval stage of S. japonicum by electroporation to induce gene mutation in a model locus. To test CRISPR/Cas9-mediated gene knock-down in S. japonicum schistosomula, we will target SjAChE and assess the degree of AChE loss using AChE activity assays. SjAChE knocked-down schistosomula will then be used to infect mice. At six-weeks post-challenge infection the mice will be perfused, and adult worms will be counted and used for further phenotypic studies. The establishment of a CRISPR-Cas9 system in schistosomes will significantly improve the ability to manipulate the schistosome genome; and will help in the identification of new drug/vaccine targets and the unravelling of drug resistance mechanisms.
- Suitable for PhD students only.