The STRE motif is known to regulate gene expression in response to cellular stress, possibly by affecting the binding of transcription factors such as NRF2 and ATF3.48, 49 We examined whether NRF2 or ATF3 binds to the STRE site by performing a super-shift assay using antibodies against these two transcription factors. A new slow migrating complex containing NRF2 was present in both B6 and D2 protein extracts but was absent when ATF3 antibody was used (Figure 3b,c). This result suggests that NRF2 mediates the expression of Per3 through the STRE element and is likely to be involved in the differential expression of Per3 in the BXD family.
