C4B and infection: Deletion of Bmal1 in primary Bmal1fl/fl neuron cultures via infection with an AAV8-Cre viral vector (versus AAV8-eGFP control) suppressed the BMAL1 transcriptional target Nr1d1 (which encodes REV-ERBα) by 85% and induced C4b expression but caused no increase in C3 (Figure 1E).