Sofosbuvir Resistance-associated Substitutions in the Palm Domain of HCV-NS5B RNA Dependent RNA Polymerase; Study of two Sofosbuvir non-responders.

OBJECTIVE

In current study we performed sequencing of palm domain of HCV-NS5B gene, its ancestral analysis along with amino acids substitution analysis. These analysis were done to find the molecular basis of the viral resistance against Sofosbuvir drug.

METHODS

Blood samples from individuals with chronic Hepatitis C infection that were resistant to Sofosbuvir were collected. The samples were processed for their molecular characterization that included RNA extraction, Complementary DNA (cDNA) synthesize, nested PCR, gel elution, Sequencing, ancestral and 3D structure analysis.

RESULTS

Evolutionary analysis revealed that current study sequences (QAU-01, QAU-02) clustered with a previously studied sequence, KY971494.1. Moreover, we reports multiple novel amino acid substitutions in the palm domain of NS5B gene such as Ile116Val, Asn117Gly, Glu246Ala, Val252Ala, Glu258Gln, Cys262Leu, Ser269Arg, Ala272Thr, Ile293Leu, Lys304Arg, Asn307Gly, Ala338Val and Arg345Gly in our query sequence (QAU-01). At 246 and 269 position in (QAU-02), no substitution was observed.

CONCLUSIONS

We have noticed that the current sequences are relatively emerging and could have been originated from aforementioned sequence recently. Based on the current results, we suggests that these substitutions could be associated with structural or functional impairment of protein and could also be may be considered as resistance associated substitutions (RAS) to Sofosbuvir drug.