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. Here, BDNF is linked to Stroke.