Fig. 3.

Knockdown of IMPDH2 in HeLa cells promotes cytoophidium assembly but does not affect proliferation rate. a IMPDH2 protein levels were analysed by Western blot in total cell extracts of iPSC and HeLa control or under IMPDH2-Kd. b IMPDH2 protein levels decrease gradually at various time points after 100 nM IMPDH2 siRNA transfection, reaching 28% in 48 h. c Immunofluorescence of HeLa cells after 100 nM IMPDH2 siRNA transfection. d Quantitative data of IMPDH2 protein level and percentage of cells with cytoophidia in b and c. e IMPDH1 and IMPDH2 mRNA levels after siRNA transfection. f Immunofluorescence of HeLa cells transfected with Non-Target or IMPDH2 siRNA for 48 h. Cells were also treated for 4 h with 1 mM guanosine or 1 mM GTP before fixation. g IMPDH2 protein level in cells transfected with Non-Target or IMPDH2 siRNA and treated with 1 mM MPA and/or guanosine/GTP 4 h before lysis. h Average size of the cytoophidium in cells under IMPDH2-Kd or MPA treatment. i The proportion of EdU-positive cells in f and g. j HPRT1 mRNA level was measured by RT-qPCR in cells transfected with Non-Target or IMPDH2 siRNA and treated with MPA and/or guanosine/GTP. Error bars means SD in d, e and h and SEM in i and j. For statistics, groups were compared by Student’s t-test with zero hour (0 h) in d and e and with Non-Target in i and j, *P ≤ 0.05, **P ≤ 0.01, ***P ≤ 0.001