MMP9 and infection: In the Lummertz da Rocha et al., 2018 study, a gene regulatory network analysis linked MMP8, MMP9, RETNLG and CD52 genes as predicted targets of MXD1. In our experimental approach using ATAC-seq data, we were able to identify MMP9 (which mediates neutrophil migration in infection (Bradley et al., 2012)) as a SEG that interact with other NSGs (CXCL8, NCF1 and TIMP3) in porcine neutrophils, but we did not detect a predicted binding motif for NSTFs in the MMP9 TSS-OCR.