A genome-wide microarray screening revealed that the mRNA levels of a myriad of pro-survival factors, such as brain-derived neurotrophic factor (BDNF), FosB and Egr1, were significantly reduced in the IRF4-KO mice following I/R (data not shown).19, 20, 21, 22 Serum-response factor (SRF), a ubiquitous transcription factor upstream of these factors that binds to the cis-acting SRE, thus activates SRE-mediated gene expression.23 Moreover, SRF is required for the neuroprotection of cortical neurons by BDNF.7 However, whether SRF protects neurons during stroke remains undefined. This evidence concerns the gene IRF4 and stroke disorder.