Cytomegalovirus colitis and haemolytic anaemia in a glucose-6-phosphate dehydrogenase-deficient immunocompetent patient

[Establishment of a stable HEK293T cell line with c.392G>T (p.131G>V) mutation site knockout in G6PD gene using CRISPR/Cas9 technique]

OBJECTIVE

To establish a stable HEK293T cell line with c.392G>T (p.131G>V) mutation site knockout in G6PD gene using CRISPR/Cas9 technique.

METHODS

We designed 4 pairs of small guide RNA (sgRNA) for G6PD c.392G>T(p.131G>V) mutation site, and constructed exogenous PX458 plasmids expressing Cas9-sgRNA. The plasmids were transfected into HEK293T cells, and the cells expressing GFP fluorescent protein were separated by flow cytometry for further culture. After verification of the knockout efficiency using T7 endonuclease Ⅰ, the monoclonal cells were screened by limiting dilution and DNA sequencing to confirm the knockout. We detected the expressions of G6PD mRNA and protein and examined functional changes of the genetically modified cells.

RESULTS

We successfully constructed the Cas9-sgRNA exogenous PX458 plasmid based on the c.392G>T(p.131G>V) mutation site of G6PD gene. The editing efficiency of the 4 pairs of sgRNA, as detected by T7E1 enzyme digestion, was 6.74%, 12.36%, 12.54% and 2.94%. Sanger sequencing confirmed that the HEK293T cell line with stable knockout of G6PD c.392G>T(p.131G>V) was successfully constructed. The genetically modified cells expressed lower levels of G6PD mRNA and G6PD protein and showed reduced G6PD enzyme activity and proliferative capacity and increased apoptosis in response to vitamin K3 treatment.

CONCLUSIONS

We successfully constructed a stable HEK293T cell model with G6PD gene c.392G>T(p.131G>V) mutation site knockout to facilitate future study of gene repair.