AICDA and infection: To confirm sparse if any Aicda mRNA expression in the CNS of tamoxifen-treated, MHV-A59-infected AIDCre-Rosa26tdTomato mice, in which AID is only expressed from one allele (4), we monitored Aicda mRNA levels in CLN relative to the levels in brains and spinal cords throughout infection (Fig. 8).