However, after infecting cells with H5N1 at MOIs of 1.0 and 1.5, the amount of SAMHD1 mRNA did not decrease as significantly as the protein level (Fig. 3A, B), and the RNA levels of SAMHD1 in samples infected with H5N1 at MOIs of 1.0 and 1.5 were still higher than those uninfected after 48 h of infection (Fig. 3B), consistent with the results at the 48-h time point in Fig. 1E. This could be due to the protein expression of SAMHD1 being subject to posttranscriptional regulation. This evidence concerns the gene SAMHD1 and infection.