H. Shimizu et al., Mutations in the 2C region of poliovirus responsible for altered sensitivity to benzimidazole derivatives, J VIROLOGY, 74(9), 2000, pp. 4146-4154
MRL-1237, [1-(4-fluorophenyl)-2-(4-imino-1,4-dihydropyridin-1-yl) methylben
zimidazole hydrochloride], is a potent and selective inhibitor of the repli
cation of enteroviruses. To reveal the target molecule of MRL-1237 in viral
replication, we selected spontaneous MRL-1237-resistant poliovirus mutants
. Of 15 MRL-1237-resistant mutants obtained, 14 were cross-resistant to gua
nidine hydrochloride (mrgr), while 1 was susceptible (mrgs), Sequence analy
sis of the 2C region revealed that the 14 mrgr mutants contained a single n
ucleotide substitution that altered an amino acid residue from Phe-163 to T
yr, The mrgs mutant, on the other hand, contained a substitution of Ile-120
to Val, Through the construction of a cDNA-derived mutant, we confirmed th
at the single mutation at Phe-164 was really responsible for the reduced su
sceptibility to MRL-1237. MRL-1237 inhibited poliovirus-specific RNA synthe
sis in HeLa cells infected with a wild strain but not with an F164Y mutant.
We furthermore examined the effect of mutations of the 2C region on the dr
ug sensitivity of cDNA-derived guanidine-resistant and -dependent mutants.
Two guanidine-resistant mutants were cross resistant to MRL-1237 but remain
ed susceptible to another benzimidazole, enviroxime. Either MRL-1237 or gua
nidine stimulated the viral replication of two guanidine-dependent mutants,
but enviroxime did not. These results indicate that MRG1237, like guanidin
e, targets the 2C protein of poliovirus for its antiviral effect.