Alterations of gene expression of neurotrophins in the DRG after HSV-1 infection. Total RNAs were extracted from L4–L5 DRGs of wild-type and Y1472F-KI mice on days 7 and 50 post-inoculation, and cDNAs were synthesized and amplified by quantitative real-time PCR with the primers shown in the Methods section. Gene expression levels of ATF3 and neurotrophins (NGF, GDNF, BDNF, and NT3) were normalized to the GAPDH level, and are presented as the fold change in the ratio of the affected side to the contralateral one. Data show the mean ± SD (n = 3–8). * P < 0.05 (Bonferroni t-test).